A Western Reversal Since the Neolithic? The Long-Run Impact of Early Agriculture

While it is widely believed that regions which experienced a transition to Neolithic agriculture early also become institutionally and economically more advanced, many indicators suggest that within the Western agricultural core (including Europe, North Africa, the Middle East, and Southwest Asia), communities that adopted agriculture early in fact have weaker institutions and poorly functioning economies today. In the current paper, we attempt to integrate both of these trends in a coherent historical framework. Our main argument is that countries that made the transition early also tended to develop autocratic societies with social inequality and pervasive rent seeking, whereas later adopters were more likely to have egalitarian societies with stronger private property rights. These di¤erent institutional trajectories implied a gradual shift of dominance from the early civilizations towards regions in the periphery. We document this relative reversal within the Western core by showing a robust negative correlation between years since transition to agriculture and contemporary levels of income and institutional development, on both the national and the regional level. Our results further indicate that the reversal had become manifest already before the era of European colonization.

cities sometimes 7,000 years old, prospering due to sophisticated irrigation management and carefully coordinated collective action.
Meanwhile, people in the Nordic countries, in the northern periphery of the Western cultural zone, continue to bene…t from peace and stability with some of the least corrupt governments the world as well as highly advanced economies. In a long-run perspective, this relative prosperity of the northern periphery is equally striking. At about the same time that massive temples and city walls were erected in the Mesopotamian cities (3500 BCE), the …rst farmers migrated to Scandinavia and settled among hunter-gatherers, bringing wheat and goats that were originally domesticated in the Middle East. Civilization in terms of statehood above tribal level, did not generally emerge here until after 1000 CE. Yet, the current income per capita in for instance Sweden is about 45 times higher than in Iraq. Is this fundamental reversal of fortune within Western civilization a historical accident?
This paper re-investigates how the Neolithic Revolution may have a¤ected modern economic outcomes through its impact on early institutions. The Neolithic Revolution was a momentous event which introduced agriculture to humans around the year 10,000 BCE.
It marked for the …rst time humans' departure from their hunter-gatherer lifestyle for agriculture and sedentary living. Our main argument is that regions in the Western core that made an early transition to Neolithic agriculture also experienced a long history of autocratic rule, intense rent seeking, and high income inequality. Due to institutional persistence, these adverse e¤ects of early agriculture and statehood eventually hampered the economic progress of the early civilizations and led to relatively low levels of development today. Conversely, regions that made the transition later were more likely to experience more democratic rule, low rent seeking and corruption, low inequality, and technological innovativeness, and ultimately a more sustained process of economic growth.
A straightforward hypothesis from this argument is that there should be a negative (reduced-form) relationship between the time since a region's transition to Neolithic agriculture and current income per capita. In order to test this hypothesis, we …rst create a new data set of countries'and regions'average date of transition to agriculture, using information from 765 georeferenced archaeological sites in Europe from Pinhasi et al (2005).
We then carry out an empirical investigation on three levels; an analysis among 1,371 European regions, a cross-regional study of 107 Italian regions, and lastly a cross-country study of 64 countries within the Western core. 1 Our results demonstrate that there is a robust negative relationship between time since transition to agriculture and current levels of GDP per capita. Although some of our historical transmission channels are unobservable, the strong association in the predicted direction between time of agricultural transition and current levels of corruption, democracy, and income equality strongly indicate that institutions are a key intermediate channel between the Neolithic transition and current development. Using historical data on proxies for economic development in 1500 CE, we further show that the reversal of fortune appears to have been in place at least 500 years ago, i.e. before Western colonization and industrialization, and seems to have manifested itself between 1000-1500 CE.
We argue that although industrialization in particular contributed critically to the massive divergence between countries that emerged during the last 200 years, our analysis suggests that the relative prosperity of North European regions followed a longer trajectory with roots in the Neolithic.
Our paper is related to a huge literature on Western economic and social history. 2 In his classic work on the long-run impact of plant and animal domestication, Jared Diamond ship on a worldwide basis, suggesting that countries that made the transition early had a long-term advantage that is still detectable in current levels of prosperity. 4 In this paper, we argue that this positive relationship is mainly driven by di¤erences between agricultural core region averages, whereas the relationship within the Western core (the region that made the transition …rst) is actually negative. 5 Figure 1 illustrates this point and also summarizes one of the key insights of the paper. The graph shows the bivariate relationship between log GDP per capita in 2005 and the time (in years) since agricultural transition for 158 countries. As the …gure shows, the relationship is positive when all 158 countries are included in the regression (black line). However, when the relationships within agricultural core areas (Western, Sub-Saharan Africa, and East Asia) are investigated separately, we see in the graph that the relationships turn negative. The negative relationship for the Western core region in the upper right corner, is the main …nding of this paper that we document in various ways.

Figure 1
In line with this evidence, we suggest a new and extended version of Diamond's model: Average income levels per capita are higher in the Western core than in all other parts of the world due to the advantages of an early transition to agriculture and civilization, but in comparisons within agricultural core areas, early adoptions of agriculture led to a relatively low level of current economic development. In the original Diamond model, Neolithic biogeography played an important role for Eurasia as a whole by introducing agriculture to the hunter-gatherers in the continent earlier than any other regions in the world. The continent in turn witnessed a headstart in technological advances and complex institutional development to support increasingly sedentary and dense population, such that the rise of statehood and empires closely followed agricultural adoption timing. In the extended version, we analyze variations within the Western core, and argue that it was the timing of expansion of the early farmers which determined di¤erent types of institutions and economic performance in the long run.
Our analysis demonstrates that the impact of the timing of agricultural adoption mattered to income levels, independent of soil quality. That is, we show that regions with same types of biogeographical endowment during the Neolithic times do not necessarily have the same income levels today. These …ndings demonstrate that the reason behind long term divergence in current incomes cannot be solely attributed to natural surroundings. For example, both Spain and Turkey were occupied by Dry Steppe vegetation at the advent of the Neolithic Revolution, but have vastly di¤erent income levels today. Furthermore, it may be that once Europe acquired the advantage of domesticable species that the Fertile Crescent introduced, Europe naturally had climatic and soil advantages relative to the Fertile Crescent. The Fertile Crescent lacked Europe's thick fertile glaciated soils and was exposed to more landscape degradation due to its dry climate. The explanation of the reversal of fortune within the Western agricultural core however still cannot be explained by biogeography alone. Various parts of Italy currently endowed with productive lands still lack the institutions that Scandinavian countries enjoy.
A second highly related tradition in the literature is the institutional view of Western long-run history, associated with North and Thomas (1973), North (1990), and a string of important contributions by Daron Acemoglu, Simon Johnson, and James Robinson, summarized in Acemoglu et al (2005a) and Acemoglu and Robinson (2012). In their most recent work, Acemoglu and Robinson (2012) downplay the importance of "geography as destiny" and argues that economic outcomes are a result of an interplay between political and economic institutions that can be either inclusive (democratic and with strong private property rights) or extractive (autocratic with monopoly rents for a favored elite).
Countries embark upon their major paths of development at certain critical junctures in history and are otherwise subject to institutional drift. 6 According to Acemoglu and Robinson (2012), such a model better explains why Britain and the United States ultimately developed institutions conducive to industrial development than models based on geography. The authors argue, for instance, that it is hard to use Jared Diamond's model of biogeographical potential to explain why peripheral Britain with its late transition to civilization could become the engine of industrialization. In the analysis of this paper, this institutional view can be reconciled with our emphasis on the crucial importance of the Neolithic. The key di¤erence is that in our model, the developmental advantages of Northern Europe in more recent history did not come about as a result of institutional drift but due to a long-run trajectory from the onset of agriculture.
A third emerging tradition in economics focuses on the importance of other long-term trajectories. Ahlerup and Olsson (2012) and Ashraf and Galor (2012) show that the spread of modern (hunting-gathering) populations out of Africa in prehistory implied that regions that were colonized late had a lower genetic diversity than in the African "homeland". Ahlerup and Olsson (2012) show that this has resulted in a lower ethnic diversity in more recently settled countries (like Sweden) whereas Ashraf and Galor (2012) demonstrate that there appears to exist a trade-o¤ between more or less genetic diversity such that countries with a medium level have had the highest levels of economic development throughout history. 7 Ashraf et al (2010), show that geographical isolation has had a positive e¤ect on economic development and argue that the result is explained by a greater reliance on own innovations in the periphery. Using newly constructed data on the levels of technological sophistication in countries from about 1000 BCE, Comin et al (2010) argue that there has been a strong tendency for technological persistence through history. When we use their data for the Western sample, we show that there has actually been a technological reversal from the origins of agriculture to 1500 CE.
In summary, we believe the paper makes the following contributions to the literature.
Firstly, we present a new theory with supportive evidence of a reversal of fortune since the Neolithic within the Western core area. Secondly, we create new data for the emergence of agriculture among all Western countries as well as among nearly 1,400 regions. Thirdly, we demonstrate how previous results of a positive association between time since agriculture and current income can be reconciled with our evidence of a negative relationship within 6 Institutional drift is a metaphor borrowed from genetics where genetic drift describes how two otherwise identical phenotypes might develop very di¤erent traits after separation over time due to random processes that have nothing to do with natural selection. See Ahlerup and Olsson (2012) for an economic treatment of cultural drift. 7 The importance of genetic di¤erences originating in prehistory is also studied by Spolaore and Wasziarg (2009). the Western agricultural core.
The paper proceeds in the following order: Section 2 describes the argument behind agricultural transition and development, whereas Section 3 introduces the data used for empirical results as well as the econometric strategy. The same section then proceeds with the empirical …ndings, whereas Section 4 discusses external validity and our extended model. Finally, Section 5 concludes by summarizing the …ndings and o¤ering avenues for future research. In his widely acclaimed work on the long-run importance of the Neolithic revolution, Jared Diamond (1997) outlines a theory arguing that societies that transited early into agriculture in prehistory achieved a head start over other societies in terms of social, political, and technological development which ultimately explained why it was Europeans who colonized the native Americans rather than vice versa. The early onset of agriculture in the Western core was in turn explained by a superior access to suitable plants and animals for domestication. 8 When the transition to sedentary agriculture was completed, civilization very soon emerged with codi…ed language, large public monuments, organized religion, hierarchical power structures, and statehood. After having experienced thousands of years in densely populated and intensely competitive agricultural states, it was only natural that the Western colonial powers could dominate most of the world outside Eurasia from 1500 CE onwards.
Later works such as Hibbs and Olsson (2004), Olsson and Hibbs (2005), Putterman (2008), and Putterman and Weil (2010) take this analysis one step further and argue that the timing of the transition to agriculture should still matter for comparative levels of wealth and institutional development around the world. Indeed, when we use data from Putterman (2006) on the date of …rst transition to agriculture for all 152 countries in the world and correlate that with log of GDP per capita in 2005, we …nd a clear positive relationship as in Figure 1. Results like these might thus be interpreted as giving support to the idea that an early transition to Neolithic agriculture is advantageous to countries even today.
However, this type of cross-country analysis has been criticized on the grounds that independent agricultural transitions basically happened within a few "macroregions" in the world such as Europe/Southwest Asia, East Asia, Sub-Saharan Africa, and in three di¤erent parts of America (Smith, 1995). For instance in Olsson and Hibbs (2005), the analysis was based on data on access to suitable plants and animals for domestication 8 Like Diamond (1997) and Morris (2010), the regions that we refer to as the "Western core" include Europe, North Africa, the Middle East, and South Asia including India and the countries west thereof. All these regions were connected through trade and migration and based their economies on domesticated plants and animals from the Fertile Crescent. for six such macro regions. The di¢ culty of di¤erentiating between areas within macro regions impeded a more complete analysis of the causality from biogeographical potential to agriculture to levels of development in individual countries.
Furthermore, when considering the history of the …rst macro region to make the transition to full- ‡edged agriculture -the Western core -it is a striking fact that some of the countries that once made up the cradle of agriculture and civilization in the "Fertile Crescent" now are relatively much less developed than countries in the periphery of the macro region. Take for instance Iraq and Syria, hosting some of the very earliest agricultural villages known to exist (around 9,500 BCE) and some of the earliest signs of civilization already by 4,000 BCE. Both countries are today close to being regarded as failed states with a very weak rule of law, a long history of autocratic government (in Iraq, at least until 2003), and stagnant economies. Compare that to for instance Sweden in the very periphery of the European/Southwest Asian zone. Sweden adopted agriculture only 3500 BCE and did not host a state above tribal level until around 1150 CE. Despite this very late start as a "civilization", Sweden (as well as most of its north European neighbors) is now one of the most economically prosperous, egalitarian, and democratic countries in the world.
Casual observations like these suggest that although the countries in the Western core doubtlessly owe some of their relatively high average levels of development to their long history of agriculture and statehood, it is less apparent that an early transition to agriculture was advantageous for comparative development within the macro region. Indeed, when we use the same data as above on time since agricultural transition and contemporary levels of GDP for 62 Western countries, there rather appears to be a negative relationship between time since transition and GDP, as shown in Figure 1.  How can we reconcile the two tendencies in the graphs above? This is what we turn to in the section below.

Our model
In an extremely simpli…ed sense, our basic model for explaining the negative reduced-form relationship between current income and time since agriculture in the Western core can be summarized by the following hypothesized causal relationship: Early transition to agriculture =) Extractive institutions =) Weak current economic performance Late transition to agriculture =) Inclusive institutions =) Strong current economic performance Figure 3 below shows a more detailed exposition of our argument . It shows the timing   of transition to agriculture as the ultimate historical factor working through intermediate   channels to a¤ect current levels of economic performance. The horizontal axis shows a onedimensional geographic space divided into regions and the vertical axis a time dimension where more recent times are found in the lower part of the …gure. Let us discuss each of these linkages in turn.

Early agriculture and extractive institutions
Firstly, speci…c geographical and biogeographical characteristics implied that the agricultural transition happened …rst in the Fertile Crescent. In this paper, we will not provide an exhaustive analysis of the determinants of early adoption. 9 We will con…ne ourselves to noting a few main factors referred to in the literature: That people in the Fertile Crescent had local access to several suitable plants and animals for domestication, the East-West axis of the Eurasian landmass facilitated the spread of food technologies due to similar mid-latitude climates (characterized by relatively wet winters and dry summers), the Fertile Crescent was centrally located along this East-West axis, and the extended founder area included rivers such as Euphrat, Tigris, the Jordan and the Nile that if properly managed could provide a steady ‡ow of water to an expanding agricultural population (Diamond, 1997;Olsson and Hibbs, 2005). In our analysis, the date of transition will thus to some extent inherently capture these speci…c geographical and biogeographical features.
It has often been suggested in the literature that there exists a strong link between the timing of agriculture and the rise of statehood (Diamond, 1997;Peregrine et al, 2007). This is also illustrated in Figure 3 where the rise of agriculture is a precursor to the subsequent emergence of statehood. Using new data on initial state formation from Borcan et al The estimated and signi…cant regression coe¢ cients for the simple bivariate association between the two variables is given by Time since …rst state formation = -5179 + 1.043 x Average time since agricultural transition (R 2 = 0:70), indicating that a country in the Western core typically developed statehood about 5,200 years after the onset of agriculture. 9 See for instance Smith (1995) or Diamond (1997) for general treatments and Ashraf and Michalopoulos (2011) for an analysis of the role of climate variation.
The slope coe¢ cient (close to unity) further implies that each year of delayed transition to agriculture roughly implied a year later transition to statehood. 10

Figure 4
An key argument in this model is that countries that made the transition to agriculture and statehood early also tended to develop what might be referred to as "extractive institutions" (Acemoglu and Johnson, 2012). Our de…nition of such extractive institutions includes unstable, autocratic forms of government with a weak rule of law, a concentrated wealth distribution largely controlled by an elite, and intense rent seeking activities, both within the country as well as from foreign aggressors. By bringing order and a capacity for collective action to previously anarchic hunter-gatherer societies, the initial economic advantages of extractive institutions in the early civilizations were often substantial. Food production was greatly rationalized which led to the emergence of specialized classes of priests, warriors, merchants, book-keepers, and engineers. Massive public monuments were erected and hordes of people from the countryside crowded into centrally planned cities.
But why and how did early agriculture lead to extractive institutions, as hypothesized in Figure 3? We believe that there are at least four reasons for such a causal link. Firstly, as mentioned above, the subsequent expansion of early agriculture into river valleys such as those of Euphrat and Tigris in an otherwise very dry area, was only made possible due to carefully coordinated collective irrigation activities involving the digging of dykes and dams, the construction of river gates, and the planning of …elds and orchards. As discussed further in the Appendix section on Iraqi history, these collective action challenges in production appear to be closely linked with the emergence and presence of centralized local power. In a famous treatise, Wittfogel (1957) even claimed that river management provided the fundament for the emergence of despotic states in Mesopotamia, Egypt and China, and similar notions can be found in the works of Karl Marx and Adam Smith.
More recently, research by Elinor Ostrom and coauthors (see for instance Ostrom, 2010) has shown that populations have often been able to solve social dilemmas such as irrigation in an e¢ cient manner without the involvement of the state. However, in a cross-country study, Bentzen et al (2012) demonstrate that irrigation potential in countries, proxied by potential yield gain from irrigation, is strongly correlated with autocratic forms of government. The result is robust to the inclusion of a range of control variables such as latitude and the fraction of arable land. Their analysis suggests that although irrigation might not necessarily give rise to states, countries with high irrigation potential tend to be more autocratic than countries that rely on rain-fed agriculture. 11 Secondly, the Euphrat-Tigris delta as well as the Nile riverbanks soon became densely populated agricultural regions with a great accumulation of wealth in urban centers. as Huns and Mongols. Also Egypt had huge accumulated wealth due to its productive agriculture, but being located somewhat more isolated with surrounding deserts, Egypt was relatively sheltered from attacks by roaming barbarians. 13 The strong correlation between the degree of centrality within the Western core and the timing of the transition to agriculture implies that variables capturing the date of the Neolithic revolution also will pick up geographical features, as suggested by Figure 3.
Fourthly, even though agriculture …rst appeared in the semi-dry areas of the Fertile Crescent, the relative advantage in terms of land fertility shifted northwestward as agriculture spread in this direction. In particular, the robust soils of continental Europe soon proved to give substantial crop yields. The river management economies of the Middle East, on the other hand, turned out to be quite ecologically sensitive. Agricultural lands in the area were under constant threat of salinization and some sources have even suggested that salinization was responsible for historical episodes of crop shifts and large-scale abandonment of certain settlements. 14 As shown by Diamond (2005), overuse of resources and ecological failures of this kind have often led to internal warfare and even social collapse.
Both the Egyptian and Mesopotamian river valleys were de facto circumscribed by desert, which made easy escape routes di¢ cult for troubled farming populations. This probably contributed to extra social con ‡ict in times of climate downturns. 15 1 3 Even Egypt was however a¤ected from time to time by invading armies. Already around 1650 BC, the Hyksos, a Semitic people, could take control of the northern parts of the country. In later centuries, also neighboring Nubians, Libyans, and Assyrians were attracted by the Egyptian wealth and managed to install short-lived foreign regimes in the country. 1 4 See Postgate (1995) for a discussion of these hypotheses. We owe the general point about ecological sensitivity to a comment by Jared Diamond. 1 5 Another potential reasons for the historical presence of extractive institutions in the Middle East, not As suggested by Figure 3, the thousands of years of agriculture and strati…ed societies gradually resulted in a worsening culture of autocratic rule and low trust which has persisted to the present day. In a companion paper to this one, Paik and Olsson (2012) show that an early transition to agriculture is associated with stronger contemporary norms towards obedience in the Western core. We argue that this culture was basically founded on the institutions of society, which in turn were founded on the structure of production.
Hence, even groups that migrated into the agricultural heartlands of the Middle East soon adopted the same extractive institutions that had prevailed among the local population for millennia. northwestern Europe, which became richer and more powerful than Italy. 16 Our model above suggests that while this shift may have been an outcome of successive waves of predation by less developed neighbors on a center, each empire or state that emerged also became progressively more innovative, learning from past experiences and mistakes.

Later transitions and inclusive institutions
As convincingly demonstrated by Bellwood (2005) and others, there are strong indications that Europe as well as the eastern parts of Southwest Asia were gradually settled by Indo-European farmers spreading from the agricultural core in the Fertile Crescent via Western Anatolia. Just like in more recent massive migrations (such as the emigration to the United States in the 19th and 20th centuries), it was almost surely marginalized groups without close access to power that …ssioned o¤ and formed new agricultural communities.
The genetic record further suggests that these colonizing farmers interbred with local hunter-gatherer populations (Bellwood, 2005). The egalitarian nature of hunter-gatherer societies probably gave another impetus towards stronger equality among these early farmers. 17 A characteristic feature of the so-called Linear Bandkeramik-culture (LBK), which spread along the Danube into central Europe and southern Germany by around 5400 BCE, was for instance a new tradition of villages with timbered longhouses hosting sevdirectly related to the transition to agriculture, includes the fact that countries in the area often became parts of large empires, which have been shown to be associated with a weak rule of law (Olsson and Hansson, 2011) and an absence of representative assemblies (Stasavage, 2011). 1 6 See also Kennedy (1988) for a classic account of how power shifted northwards from around 1500 AD in Europe. 1 7 In a very extensive combined study of primitive agricultural, horticultural, and hunting-gathering societies around the world, Mulder et al (2009) provide empirical evidence of a substantially higher income inequality among agricultural communities than among hunter-gatherers. See also Sahlins (1973). eral families, suggesting a relatively egalitarian social structure and a ‡uid pattern of land ownership (Bellwood, 2005).
Eventually, also many of these new communities would accumulate wealth in urban centers and become the object of predatory attacks from more primitive neighbors. Wealth accumulation, combined with exogenous threats and a growing population, thus typically led to a gradual shift towards more autocratic rule also in these communities. However, the historical tradition of autocratic rule would be weaker and less pervasive in these societies than in the Middle East. Furthermore, the underlying geographical conditions in most core areas of Europe (such as the absence of major river valleys and the reliance on rain-fed agriculture) were still not as conducive to the maintenance of highly centralized, autocratic, urban states as in the eastern Mediterranean.
Consider for instance the territory of Italy, a centrally located region in Europe and of key historical importance for the history of the continent. The archaeological record suggests that the peninsula was originally populated by Neolithic farmers from the Eastern Mediterranean during the 7th millennium BCE. 18 As shown in Figure 5, the …rst sites are predominantly found in the south-east. The north-central areas, roughly stretching from current Florence to the Alps, was the region where agriculture emerged the latest after 5200 BCE. Italy during the Roman Republican era was clearly a society with more equally dispersed wealth and power than during the subsequent Imperial era (starting with the rule of Augustus in 27 BCE). As recently emphasized by Acemoglu and Robinson (2012), the republican institutions with a senate as the center of power and with executive power in the form of consuls on a one-year tenure, combined with o¢ ces for representatives of the people such as tribunes, guaranteed a relatively widespread distribution of power. This gradually changed with the emergence of powerful generals who would become more and more in ‡uential politically until they could rule as autocratic emperors in a similar style as many Eastern rulers before them. Although Imperial Rome was very successful economically at least until the late 2nd century CE, income inequality and rent seeking increased From around 1500, Spain became a major in ‡uence in southern Italy and for long periods ruled over the area. The Spanish feudal institutions were quite di¤erent from the institutions of northern Italy. Representative assemblies did not emerge during the Renaissance in this part and when Italy was united in 1860, it was already clear that the south was relatively backward, economically as well as institutionally.
To summarize, Italy clearly made the transition to agriculture later than in the Fertile Crescent and experienced a later rise of statehood and autocratic rule during imperial Roman times. But the peninsula as a whole still had a substantially shorter history of autocratic rule than the regions in the eastern Mediterranean and the northern cities even experienced periods of inclusive institutions.
Only in the most distant periphery of the western region, in Northwestern Europe, were the conditions decidedly not conducive towards the early emergence of autocratic, centralized states. The shores of the North Atlantic and the Baltic Sea were conquered quite late by farmers and probably faced tough resistance from relatively prosperous huntergatherers who lived well o¤ the rich aquatic resources in the area (Bellwood, 2005). For instance, Denmark only made the transition to agriculture around 3500 BCE and to statehood 700 CE. Soils were further of poorer quality than on the North European plains which hindered the emergence of urbanism and high population density.
Communities in this part of Europe were relatively protected from predatory attacks by other peoples. 19 Pagan Vikings from the Scandinavian countries raided several regions of Europe around 800-1000 CE and Viking colonizers assumed power in Russia (Novgorod), England, and Normandie. However, due to their geographical isolation and relatively infertile soils, these North European regions were largely spared from attacks by invading armies. 20 Absent this constant military threat and with no ancient culture of autocratic 1 9 See Ashraf et al (2010) for an analysis showing that geographically isolated societies in prehistory tend to be relatively rich today. The authors argue that plausible channels for this relationship is protection from predation and a stronger reliance on indigenous innovative activity.
2 0 Sweden, for instance, fought many wars throughout its short history with the Danes and on the rule, the people in these areas could maintain relatively egalitarian institutions with a stronger rule of law and with relatively in ‡uential popular assemblies. With no substantial concentrated wealth to capture, internal rent seeking and corruption never turned into a serious problem and foreign powers remained uninterested in conquering the northern areas.
In summary then, the countries that made the transition to agriculture …rst also experienced a long history of unstable, autocratic rule with a weak rule of law, high inequality and substantial rent seeking, internally and externally. The main reasons for this were related to the close association between irrigation technology and centralized power, the attraction of accumulated urban wealth on predatory neighboring peoples, their central location between east and west, and the environmental degradation that the …rst agricultural areas soon experienced. In central and western Europe, there were both periods of empires and autocratic rule as during the Roman and Frankish periods but also long periods of less autocratic states. In northern Europe, the transition to civilization happened late and hierarchical institutions like those in the original agricultural zones were not observed for any extensive periods. Authoritarian norms were never ingrained in society to the same extent as in the early civilizations.

Institutions and economic performance
The last intermediate link between transition to agriculture and current economic performance in Figure  Finally, the last link in Figure 3 suggests that the inclusive institutions favoring technological innovation that were prevalent in the northern periphery, should imply a stronger economic performance during the more recent stages of history. Analogously, the extractive institutions and weak incentives for innovation that characterized the early agricultural societies for several millennia, should imply a weak economic performance today. But continent, but its heartlands were never overrun by a foreign army. Because of its recent neutrality, the country has not been engaged in a single war during the last 200 years. See Appendix 1 for an extensive analysis of Swedish history in a comparative perspective.
when in history did the extractive economic institutions run into diminishing returns so that the reversal became manifest? After all, polities based on extractive institutions such as imperial Rome or Byzantium could thrive economically well into the Middle Ages.
From the point of our model, one would expect a reversal to start working in an era characterized by a technological paradigm that rewarded individual innovative e¤orts rather than central coordination. According to many accounts, the late Medieval period between roughly 1100-1500 CE was such a period (Mokyr, 1990; Morris, 2010). As already mentioned, the North Italian cities started to ‡ourish culturally and economically during this period. Similar developments took place further north in the Flandern region. Also Dutch and North German cities became important centers of manufacturing and trade.
Representative assemblies appeared and both science and technology made great strides.
As will be shown below, by 1500 CE, countries that made a late transition to agriculture and civilization had become the …rst to develop inclusive institutions, which in turn had given them a decisive economic edge by the start of the Modern era compared to competing nations further south. 3 Empirical analysis

Data
The key explanatory variable in the empirical analysis is the time since the Neolithic transition. 21 Figure 6 shows the geographical distribution of all sites in the sample. The use of a detailed set of carbon-dates spread across Europe allows for a measure of the initial agricultural adoption dates for each speci…c region in consideration. The average initial date of agricultural adoption is obtained by using the inverse distance weighting method and zonal statistics in ArcGIS. Appendix 2 shows the inverse distance formula used for the calculation. For the analysis, we obtain the average adoption date for each region or country by …rst interpolating the point data across the excavation sites and then calculating the mean date within the administrative border. Figure 5 shows an example of this methodology applied to the 78 Neolithic sites within Italy.
Taking the year 2000 as the benchmark year, the mean time since agricultural transition in our cross-regional sample is 7,055 years with a range from 5,243 to 11,320 (Appendix 4). This of course translates into a mean adoption date of 5,055 BCE and a …rst adoption date of 9,320 BCE. In the cross-country sample, the mean is 7,611 years, the minimum is 5,608 (Denmark) and the maximum 9,743 (Syria) (see Appendix 6).
Most cross-country studies that include the time since Neolithic transition as a variable have so far used the cross-country data set in Putterman (2006). For each country, Putterman (2006) determines a date of transition by using the …rst attested date of Neolithic agriculture within the country's borders as stated by various specialized sources.
We believe that our methodology o¤ers several advantages as compared to Putterman (2006). As far as we know, the data in Pinhasi et al (2005) o¤er the most recent and most comprehensive compilation of transition dates for the Western region. Furthermore, our methodology provides the average date of transition for a country rather than the …rst date of transition, as in Putterman (2006). 22 We believe that this practice will more accurately re ‡ect the transition for the whole country since there might be large discrepancies in dates of transition between regions within countries, as also acknowledged by Putterman (2006). With our methodology, it is further possible to determine transition dates on a much …ner geographical level.
We  The dependent variable in our regional and Italian analysis is the mean intrastate

Econometric strategy
In our model in Section 2, we outlined a theory including three basic causal linkages: 1.
Time since transition to agriculture )2. Institutions ) 3. Current economic performance.
In our econometric framework, we will mainly use data on 1 and 3 and we recognize that some of the institutional factors in 2, involving the often long historical experiences of countries and regions, are not always readily observable. The main focus of our attention will be on assessing the impact of the times since the transitions to agriculture on economic and institutional outcome variables that we have the most reliable measures on.
We will most often run reduced-form equations of the very simple form where Y i is income per capita in region or country i in our Western sample, T i is the time since agricultural transition, X i is a vector of control variables, and i is a normally distributed error term. The parameter of interest in this setting is of course 1 , showing the reduced-form impact of agricultural history on economic performance. In the case when Y i refers to the current income per capita of some country or regions, our hypothesis is an adverse long-run impact of agricultural experience on economic prosperity.
A key identifying assumption in this setup is of course that Y i did not in any way in ‡uence T i . As has been discussed in previous chapters, once agriculture was invented in the Fertile Crescent, it gradually spread towards the northwest in a fairly regular pattern.

Results
In this section we document the negative, reduced-form relationship between time since agricultural transition and levels of current economic performance. In the cross-country part, we also analyze the historical evolution of this relationship and make an assessment of the importance of institutions as an intermediate link. We use three levels of analysis: 1,371 European NUTS-3 regions, 107 regions within Italy, and lastly a cross-country study of 64 Western countries. Table 1 shows the results for the cross-regional analysis among 1,371 Western regions in 30 European countries. 24 In the …rst six speci…cations, the coe¢ cient value for the agricultural adoption date variable is strongly negative and statistically signi…cant, even though the magnitude of the coe¢ cient drops when the set of Neolithic vegetion variables are included in Columns 3-6. Table 1 The The negative and signi…cant relationship between income levels and agricultural transitions dates is however not robust to including country …xed e¤ects in Column 7. Hence, we cannot rule out that variation between countries is driving the regional results in Columns 1-6. In order to investigate this issue in more detail, we conduct the following analysis in two ways. First, we run an in-depth analysis of within-state variation by focusing only on one country -Italy -for reasons explained below. Second, we carry out an extensive cross-country analysis to explore the reduced-form relationship further and to analyze the channels through which the timing of agricultural adoption in ‡uenced modern outcomes at the country level.

Italy
Italy provides a suitable setting for which the above hypothesis can be tested. Its geographical location on an axis from southeast to northwest gives it the same spatial orientation as the direction of the historical spread of agriculture across the continent, as shown in Figure 6. The country is geographically placed in the middle of the agricultural spread and in the Mediterranean region, made up the core area of the Roman Empire, and has a rich set of 78 archaeological sites to infer local di¤usion of agriculture. Furthermore, the country is divided into 134 di¤erent regions, 107 of which we have income data for comparison. These regions have also been the focus of institutional and cultural research for their varying institutional performance despite close proximity to each other and despite belonging to the same country for about 150 years. 25 The broad contours of the country's history since the Neolithic were presented in Section 2.
The maps in Figures 9-10 show the average dates of transition to agriculture and average income levels per capita, respectively. The southern regions adopted agriculture early on, while northern regions adopted agriculture later, an observation which is consistent with the pattern of di¤usion in the rest of the European continent. In particular, the north-central regions of Italy were late to adopt and are now the wealthiest areas of the country. Visual inspection suggests that there is a strong negative correlation between date of transition in Figure 9 and current income per capita in Figure 10.

Cross-country analysis
The main results for the cross-country analysis are shown in Table 3. The sample includes 64 Western countries in Europe, Middle East, North Africa, and Southwestern Asia that belonged to the Western core of agricultural di¤usion. The cross-country sample thus contains more than twice as many countries as in the cross-regional analysis. Appendix 6 provides descriptive statistics for the included variables. 2 5 See for instance Ban…eld (1958) and Putnam (1993). Ban…eld (1958) studies the e¤ect of culture on the success of institutions in these regions. The author …nds "familial amoralism" as the dominant ethos in Montegrano in Southern Italy: "Maximize the material, short-run advantage of the nuclear family; assume that all others will do otherwise." The result of such cultural values, according to Ban…eld, is the main cause for the backwardness in Southern Italy.
Following Ban…eld, Putnam (1993) refers to the absence of "civic virtue," or the character of the citizens showing "interest in public issues and devotion to public causes" (Walzer, 1992), as the main determinant for the lack of institutional performance in the southern regions of Italy. Importantly, the author traces the di¤erences of institutional performances in South and Northern Italy back to the year 1100, arguing that Northern Italy's merchant ruling class with horizontal social networks and active social involvement led to better institutional performance than the South, a region marked by a history of autocratic rulers. Table 3 As is clear from the table, Average time since agricultural transition in the Western core has consistently a negative and signi…cant impact on log income per capita in 2005.
Like in the previous tables, we also include a number of geographical control variables such as country area, the percent of arable land, and the average altitude of the country.
Interestingly, Log Arable land is negative and signi…cant in Columns 2-4, but not in the other columns.
Obviously, the countries in our Western sample have been strongly a¤ected by other historical events apart from their transition to Neolithic agriculture. Starting in Column 3, we try to account for some of these other in ‡uences by including variables proxying for the in ‡uence of Atlantic trade (Atlantic coastline to area-ratio), the impact of being part of the Roman, Byzantine, and Ottoman empires (measured as the fraction of a country's territory within each empire at the time of their maximum extension), and whether the country was a previous Warsaw pact, East European country or a former Soviet republic.
In the full Western sample, former Roman countries appear to have higher GDP and former communist countries have a substantially lower GDP.
When the standard set of controls (used in tables below) is employed as in Column 4, time since agricultural transition is still negative and signi…cant. The conditional scatter plot for this regression is shown in Figure 10  A potential objection to using the full Western sample is that it includes a quite heterogenous group of countries, mixing European states with North African and Middle Eastern countries. In Columns 5 and 6, we therefore restrict our sample to 40 European countries. Within Europe, the former communist dummy is very signi…cant, as expected, but so is time since agricultural transition. In Columns 7 and 8, we restrict the sample even further to only include 31 countries that had more than 50 percent of its territory within the Roman empire in year 200 CE. These countries shared a similar institutional and cultural context during a very formative period of Western history. The precision of the estimates for our main explanatory variable is even better in this sample.
In Table 4, we check the robustness of our results in a number of ways. We start by using two alternative measures of time since agricultural transition. First, we include  Table 4 In Given these results, we …nd it very unlikely that our main explanatory variable is mainly 2 6 See Appendix 6 for the descriptive statistics regarding this variable. Compared to the Average date of transition, the cross-country mean level of Earliest date of transition is 835 years higher. 2 7 Note that the estimates for vegetation variables that are never signi…cant in the regressions are not displayed in the table. For the Malthusian era, it is widely accepted that population density is a good indicator for the level of economic development in a country (Ashraf and Galor, 2011). In Table   5, Columns 1-3, we use population density in years 1, 1000 and 1500 CE as dependent variables. In year 1, the reversal does not seem to be in place since the estimate for Average time since agricultural transition is positive. In 1000 CE, the estimate is negative but insigni…cant. However, by 1500, the reversal is evident since time since agricultural transition in that year has turned negative. Table 5 In Columns 4-6, we instead use Log GDP per capita from the same time periods as the The results in Table 5 strongly suggests that the historical heritage from the Neolithic turned from being an asset to Western countries' levels of development as late as 1000 CE, to being a drag only 500 years later, and from then on until today. In Table 6, we investigate the time period 1000-1500 CE further by using the population and GDP per capita growth rates as the dependent variables. As expected, Average time since agricultural transition has a statistically signi…cant negative in ‡uence on both population and GD per capita growth rates during the period. Since the initial levels of population density and income levels are included in Columns 2 and 4, this is not a simple convergence e¤ect. Table 6 In …gure 11, we show the bivariate association between GDP growth and time since agricultural transition from the speci…cation in Table 6, Column 3. The …t among these 21 countries is rather high with a R 2 of 0.52. Not surprisingly, Renaissance Italy and Belgium are outliers with superior growth rates. In the upper left corner are the North European countries and in the lower right, the early civilizations with weak growth. The point estimate of -0.0347 in Column 3 implies that a 1000 year earlier transition to agriculture is associated with an annual growth rate that is 0.0347 percentage units lower. This might seem like a small e¤ect but during this medieval period, when the mean annual growth rate in our sample was a modest 0.069 percent, the economic signi…cance was not negligible.

Figure 11
We do not interpret these results as evidence against the critical roles played by Atlantic trade, the Reformation, and the Industrial Revolution. Undoubtedly, these fundamental processes contributed very importantly to the great divergence that made Britain and its northern followers so much richer than the Mediterranean and Middle Eastern countries.
What we do suggest, however, is that the process of reversing fortunes in the Western world seems to have followed an older trajectory rooted in the Neolithic which has previously not been recognized and which seems to have become manifest already during the Medieval period. We leave it for future research to investigate further why the reversal happened in 1000-1500 CE and not in some other period.
In Table 7, lastly, we analyze the in ‡uence of Average time since agricultural transition on our intermediate variable; historical and current levels of institutional quality. If our hypothesis is correct, we should observe that by 1500 CE, time since the Neolithic should already have a negative in ‡uence on democratic and private property-related institutions.
In Row 1, the dependent institutional variable is Executive constraints in 1500 CE, taken from Acemoglu et al (2005b), and believed to capture to what extent governments were constrained from expropriating private property. As predicted, Average time since agricultural transition has a negative impact on Executive constraints in 1500, meaning that later adopting countries had stronger institutions already by this time. Table 7 In , and the level of democracy/autocracy (Democracy in 2010 ). 28 Given the path dependency of many institutional indicators, we also expect that the current levels should be correlated with historical levels, although we unfortunately do not have comparable historical measures readily available to test this argument.
As we see from the table, countries that made the agricultural transition early tend to have relatively more corruption, be strongly autocratic, and have a substantial income inequality. This does not change when control variables are included. A potential objection to this analysis is that the institutional variables used above mainly capture the formal rules or compliance to rules at a speci…c and recent point in time. For instance, the scores for Democracy in 2010 are obtained from the Polity data set where scores can sometimes change drastically from year to year for a speci…c country. In a companion paper (Paik and Olsson, 2012), we speci…cally investigate the impact of the transition to agriculture on informal institutions and cultural norms that are likely to change in a much slower fashion.
Our results show for instance that norms towards obedience are also more prevalent in regions that transited early, in line with our model. Argentina is a lot richer today. However, the main reason for this substantial di¤erence in population density in pre-Columbian times is the very di¤erent agricultural histories of the two countries. Western Bolivia was part of the Andean highland civilization that made the transition to agriculture around 2000 BCE, based on the cultivation of squash, beans, potato, and avocado (Bellwood, 2005). The dominant city of Tiwanaku hosted between 15,000-30,000 people already in 600 CE (Kolata, 1993). Argentina, on the other hand, was peripheral to the major early civilizations and the largely nomadic tribes in the area only developed primitive agriculture. In pre-Columbian times, no urban settlement hosted more than a few thousand people.

External validity and an extended model
Hariri (2012) likewise argues and demonstrates empirically that regions outside Europe that had a long history of agriculture and of statehood tended to provide a stronger resistance to the colonial powers when they …rst appeared after 1492. Some of the oldest civilizations, like China and Ethiopia, were never colonized at all. Unfortunately, this also meant that their highly autocratic institutions were resistant to Western ideas of democracy and inclusive institutions that were transplanted to many countries with weaker indigenous state formations (like Australia and Argentina). In this way, early agriculture again implied a curse to long-run development.
In this paper, we have focused on establishing a causal relationship for the Western core to believe that the same pattern of an early transition to agriculture, followed by autocratic rule, rent seeking, inequality, technological backwardness, and ultimately stagnant economic development has also prevailed within other agricultural core areas.
In Figure 12, we look at the unconditional correlation between log GDP per capita in 2005 and Putterman's measure of agricultural transition among 41 countries in Sub-Saharan Africa. All these countries are part of the Sub-Saharan zone where agriculture spread mainly from an early core in the Sahel (Diamond, 1997;Bellwood, 2005). As the …gure shows, there is a robust and surprisingly strong negative relationship. Northeast  The pattern in Central and East Asia is described by Figure 13. The simple relationship is clearly negative and signi…cant at the 10-percent level. 29 China (CHN) was the …rst country to adopt agriculture and is somewhat richer than predicted by the model, whereas Japan (JPN) and Singapore (SGP) are late adopters that are relatively rich in an Asian comparison. Figure 13 In the Americas, any analysis of a relationship between transition to agriculture and current income levels is extremely complicated due to the demographic shift that happened there since 1500 CE. It is a well-known fact that disease and hardship caused a very large fraction of the native Indian population to become extinct and be replaced by European immigrants and slaves from West Africa. Hence, we refrain from drawing any conclusions on the basis of the American case.
In Figure 1 An equivalent mid-range country in East Asia made the transition somewhat later, by about 6,500 BP, and has a much lower log GDP per capita at about 7.5 (1,810 $US).
The equivalent numbers for Sub-Saharan Africa are roughly 2,600 BP and a log of GDP at 6.24 (515 $US). We argue that these large continental di¤erences in average levels of development can be well explained by the advantages of a superior biogeography and geography and an earlier transition to agriculture and civilization in the Western core, as argued by Diamond (1997). However, within the Western core, the relationship is clearly negative, as discussed above. 30 The …gure provides a way of reconciling the Jared Diamond-hypothesis with the institutional reversal-hypothesis outlined in this analysis. To a great extent, the positive relationship for the whole sample is driven by the successive negative relationships for the Western, East Asian and Sub-Saharan African cores. Although the evidence from East Asia and Sub-Saharan Africa are clearly inconclusive at this stage, they are consistent with the basic pattern demonstrated for our Western sample. We believe that the relationships that emerge from Figure 1 might serve as the basis for a new hypothesis regarding the long-run impact of early agriculture.

Conclusions
In this paper, we argue that whereas countries that made the transition to agriculture early tend to be relatively rich in a worldwide comparison, there is a reversal of fortune within the agricultural core regions in the sense that early adopting countries tend to be poorer today than the countries in the periphery of the core. Our model suggests that the reason for this reversal is that countries and regions that made the transition to agriculture early tended to develop autocratic, unstable states early in history, characterized by rent seeking, inequality, and technological inertia, while later adopting regions had more democratic forms of government, less rent seeking, and a greater social equality.
In the empirical section, we demonstrate that there is a strong negative association between time since transition to agriculture and current income levels in regressions featuring 1,371 European regions, in a study of 107 Italian regions, as well as in a cross-country analysis of Western countries. We also show that time since agricultural transition is associated with early statehood, high corruption, autocratic forms of government, and great inequality. Importantly, the economic, institutional, and technological reversal appears to have been in place already in 1500 CE, i.e. before Western colonization and industrialization. Hence, the very large income di¤erences that emerged during the last 500 years seem to be partly rooted in development trajectories dating back to the Neolithic.
Our analysis ends with a brief investigation of the external validity of our hypothesis outside the Western core. Preliminary …ndings from Sub-Saharan Africa and East Asia, as well as our interpretation of the existing literature, strongly suggest a positive association between time since agricultural transition and current income on a worldwide basis, combined with a negative association within core areas. The …ndings also warrant a more careful analysis in the future of the links between agricultural transition and long-run economic development outside the Western core.

Appendix 1: Comparative country analysis
In order to illustrate the logic of our model further, we will in this section make a more detailed comparative country analysis, using spread to the whole region (Diamond, 1997;Bellwood, 2005). Animals such as goats and pigs were domesticated somewhat later, presumably on the ‡anks of the Zagros Mountains (Smith, 1995;Diamond, 1997). A few thousand years later, they would be complemented with cattle and horses.
One of the oldest archaeological sites in northern Iraq is Qermez Dere, with an agricultural settlement from about 9000 BCE (Pinhasi et al, 2005). One of the most notable …ndings on this site was three circular, underground chambers …lled with tons of soil, Several instances of headless burials could potentially be interpreted as human sacri…ce.
Some of the largest settlements, such as Abu Hureyra in Syria, hosted around 5000 people already by 8000 BCE (Bellwood, 2005). Houses with own storerooms and kitchens would soon emerge. Together with the almost obsessive reverence of ancestors, these social changes indicate a society with important public goods but also one where private property started to matter and where land was inherited from one generation to the next digging earthen dykes that protected …elds from ‡ooding water. In order to be e¢ cient, the structure of the irrigation system had to be planned and work carefully coordinated.
A failure at any link in this highly sensitive system might have disastrous consequences for the village. 1 Workers further had to be fed and provided with e¤ective tools and the structure of …elds and cultivation had to be carefully planned (Postgate, 1995).
All these characteristics of the new production technology implied pressures towards creating a strong centralized power. In the rural villages, irrigation management was coordinated by an o¢ cial referred to as gugallum (Postgate, 1995, p 178). It is certainly straightforward to think of this kind of social organization as being the driver of the further development towards more centralized power in the villages which eventually resulted in full-blown city-states. The famous hydraulic hypothesis of Wittfogel (1957) proposes that the nature of water management in Mesopotamia, Egypt, and China was responsible for the rise of highly centralized states in these regions. 2 Exactly how causality worked between collective water management and centralized rule in Mesopotamia remains to be established, but the association is in any case clear.
A climate downturn around 3800 BCE with even less rain and less reliable ‡ooding of the rivers, put a great strain on the already fragile ecological system of Mesopotamia.
It has been suggested that this downturn provided a further impetus towards a more e¢ cient organization and use of resources (Morris, 2010). Only the cities that succeeded in this endeavour survived and most likely experienced an in ‡ow of people from collapsed communities. 3 One of the oldest cities in the area was Eridu where the earliest settlement dates back to 5400 BCE. Archaeological excavations have revealed that the city hosted a succession of temple structures, built on top of each other, with the earliest small shrine dating to 5000 BCE (Postgate, 1995).
During this period, Uruk emerged as a leader among the growing cities in the area and soon became very in ‡uential culturally, not only in Mesopotamia but also in neighboring lands. Around 3500 BCE, the …rst statehood arose. This event is generally viewed as the onset of what is usually referred to as civilization. The Sumerians in Uruk invented cuneiform writing around 3300 BCE, inscribed on clay tables, and used bronze on a large scale by 3000 BCE. The massive temple area was clearly the home of a very powerful "priest-king", managing a temple economy that controlled substantial areas of agricultural land as well as farm labor to work its …elds. The clay tablets that have been recovered often record temple production quotas. A highly specialized labor force worked in the temples apart from the priests, including accountants, guards, water-carriers, weavers, boatmen, barbers, and musicians, as well as regular slaves (Postgate, 1995). The temple most likely also organized the long-distance trade that brought foreign luxury goods to Mesopotamia and contributed to the more e¢ cient mining of metals like bronze and copper. Humble citizens presented regular o¤erings to the gods (and food rations to the temple sta¤) and were often sent to war on neighboring city-states in large military campaigns. The city of Uruk is believed to have covered around 400 hectares with a 9 km town wall (Postgate, 1995) and presumably hosted around 20,000 individuals, packed into carefully planned mud brick dwellings (Morris, 2010).
Uruk's eminence in Mesopotamia ended early in the 3rd millennium BCE for unclear reasons but their power had anyway always been more cultural than political. The southern part of Mesopotamia remained for several centuries a land united by a common Sumerian culture but where rivalling city-states often fought each other and remained largely independent. In this sense, Mesopotamia after Uruk was more similar to the highly fractionalized pre-Hellenic Greek system of city states than to neighboring Egypt, which was led by a single ruler. Unlike the riverine type of farming practiced in Mesopotamia, agriculture in Sweden was always rain fed, implying a weaker need for a centralized organization of the economy.
As elsewhere in the Atlantic parts of Northern Europe, the construction of megalithic tombs were a common feature of early farming communities, suggesting an increased reverence for the dead and an emerging organization for the provision of public goods.
Copper was used by these early farmers but the metal was not widespread and presumably imported. Bronze was not widely used until about 1500 BCE, a change which most likely revolutionized warfare and social organization. During the latter part of the period, very large burial mounds suggest an increase in social strati…cation although not beyond tribal level (Welinder, 2009).
The use of iron became widespread in Sweden around 500 BCE. The Scandinavian countries did not become part of the Roman empire but were nonetheless a¤ected by 5 The culture is referred to as TRB and shares many features with the so called "Ertebölle" culture of Denmark from the same period (Bellwood, 2005). developments on the continent. In particular, the collapse of the Western Roman empire in the 5th century CE and the massive migrations during the period, resulted in a period of social unrest in Sweden, manifested in the construction of multiple defensive forti…cations.
By 550 CE, a more peaceful period referred to as "Vendel" started in Sweden when tribal chiefs in various parts of the country could establish rule over extended regions and were buried in impressive burial mounds. The greater concentration of wealth was due to a centralized control over iron mining and the establishment of trading centers which greatly increased imports and exports. The chiefs controlled forces of mounted elite warriors with costly weaponry, o¤ered pagan ceremonies in wooden halls, and oversaw the production of jewelry in gold (Welinder, 2009). Primitive writing in the form of runes were carved into stone.
In the latter part of the 700s, the trading post Birka was founded in Lake Mälaren by a local unidenti…ed chief and quickly emerged into the …rst urban settlement of Sweden.
However, even at its peak, the size of the population still did not exceed 1000 individuals. Traded goods from many parts of the world have been excavated, including Arabic countries. Christian missionaries appeared in the town in the 830s but failed to establish Christendom in the area.
By 800 CE, Sweden was still very much a periphery in the Western world; culturally, economically and politically. However, population growth had been rapid since the great migrations ended and local chiefs had accumulated the power to equip troops with expensive weaponry and horses and to build long ships that were capable of making long sea voyages. In 793, a ‡eet of such ships reached the monastery of Lindisfarne in Northern England, which was subsequently looted and the local population terrorized. This attack is usually regarded as marking the beginning of the Viking Age in the Scandinavian countries.
The Viking attacks on the more developed parts of Europe that started around 800 basically followed the same pattern as so many other attacks by primitive peoples on more advanced core regions. The wealthy cities of Mesopotamia were overrun by neighboring tribes who had adopted the basic military technology of the center but were still not integrated into its urban civilization. In the same manner, the Vikings looted numerous towns and monasteries in Atlantic Europe, around the Baltic Sea, as well as in the Mediterranean.
Vikings formed new kingdoms in England and Normandy, settled Iceland and Greenland, served as mercenaries to the emperor in Constantinople, and even formed a temporary colony on New Foundland. Eventually, the Vikings outside Scandinavia blended with the local populations, settled down and were Christianized.
When Viking energy subsided in the 11th century, there were kingdoms and states in Norway and Denmark but still not in Sweden. The two core areas, Svealand around Lake Mälaren and Götaland in the southwest, were not easily united and were divided by deep forests. The country was eventually Christianized by 1100 and not until around 1150 was the country united under a king. From this period onwards, Sweden is considered to have had a government above tribal level but with a very weak state and a king who had to struggle to maintain jurisdiction over local chiefs and independent bishops. Not until the era of Birger Jarl, a strongman from Götaland whose son inherited the throne, was the Swedish state consolidated around 1250, almost …ve thousand years after the initial emergence of agriculture.
As can be seen in …gure 6, the date 1250 also marks the time when Sweden overtook Iraq in terms of strength of statehood. In 1258, Iraq was overrun by yet another foreign people, the Mongols, an event which ended the golden era of Arab culture in the region.
In peripheral Sweden, in contrast, no foreign peoples ever sought to invade the sparsely populated and culturally backward country, lacking proper cities and fertile farming lands.
Traders from the German towns by the Baltic Sea dominated economic life in Sweden throughout the Middle Ages but were never interested in the land as such. As elsewhere in Europe, feudalism was the main economic organization of the countryside, but peasants were generally a lot more independent than in for instance Eastern Europe. In 1393, Sweden entered a union with its more powerful neighbor Denmark which would remain until 1523, when the founder of the modern Swedish state, Gustav Wasa, defeated the Danes, renegotiated debts with the German trading towns, suppressed local rebellions, and …nally established Sweden as a fully sovereign state.
In the early 17th century, Sweden adopted Protestantism and rose in the Thirty Years' War (1618-1648) to become a major military power in northern Europe, mainly due to its superior organization of taxation and military service. Once again, Swedish armies pillaged continental Europe and contributed to the long decline of the Holy German Empire. Also Poland was badly ravaged during the rule of the constantly campaigning Charles X. New territories were conquered from Denmark in the south and substantial amounts of war booty enriched a nobility from which most of the military commanders had been recruited.
Inspired by the autocratic rule of Louis XIV in France, the Swedish kings Charles XI and Charles XII ruled without taking much advice from parliament. After the decisive Swedish defeat against Russia in 1709, Sweden's period as a north European superpower was e¤ectively over.
When Charles XII died in 1718, a new era started when the king had to secede substantial powers to the parliament. Not even the attempts by Gustav III to restore autocratic rule were successful and the king was even murdered in 1792. Sweden was clearly not characterized by social equality in the modern sense during this period, but the farming population was relatively free and protected by law. After its involvement in the Napoleonic wars in the early 1800s, Sweden adopted a principle of neutrality and has not been engaged in any war since.
Free from military threats domestically and campaigns abroad, the country entered a road towards an even stronger parliament and a widened su¤rage. A massive emigration of poor Swedish peasants to the United States in the decades after 1850, eased a growing problem of overpopulation in the countryside. During the strong social tensions after World War I, which swept away the old regimes in so many European countries, universal su¤rage of all men and women was introduced in 1921 and the Social Democratic Party was allowed to dominate Swedish politics from 1932 onwards. Since the country was spared war damages in World War II due to its neutrality, the speed of industrialization picked up even further when the demand for Swedish goods surged. Extensive social reforms and progressive taxation turned Sweden into one of the most equal societies in Europe. Not even the very serious economic crisis of the early 1990s altered the general trend of rising prosperity.
By 2012, Sweden is one of the richest and least corrupt countries in the world and has the strongest public …nances in the European Union. 6 Like in the neighboring Scandinavian countries, there are no signs of social unrest, even in the wake of the …nancial crisis.
In summary, Sweden's late transition to agriculture and to statehood, in combination with its geographical peripherality and relatively unproductive farming lands, implied that the country was not a natural target of predation by neighboring peoples or by rent seeking local lords. Wealth was relatively evenly distributed through most of history and not even the attempts by the militarily powerful kings of the 1600s succeeded in permanently establishing autocratic rule. Due to the great degree of social cohesion, the social reforms after World War II could be peacefully installed without alienating capitalists and the upper classes. In so many ways, Sweden's history was the direct opposite of that of Iraq.
Additional references:

Appendix 2: Inverse Distance Weighted Interpolation
The …rst step of calculating the average adoption date for a given region is interpolating observed points of archaeological sites. For each cell S 0 on the map, the formula used in interpolation is as follows (Johnston-2003): where: Y (S 0 ) is the predicted adoption date for location S 0 .
N is the number of measured sample points surrounding the prediction location that will be used in the prediction. Here N is set to 15. i are the weights assigned to each measured point. Y (S i ) is the observed value at the location S i , one of the known archaeological sites.
The formula to determine the weights is the following: The power parameter p, which is determined by minimizing the root-mean-square prediction error (RMSPE), is 2. 7 In determining the adoption date of a given area, the paper assumes that the archaeological site closest to the area gives best information on the approximate date of agricultural adoption, given the cost of travelling from one place to another and the similarity of landscape of adjacent areas. That is, IDW considers proximity to each area to be the most important factor in estimating adoption dates. IDW method is used to obtain the average adoption date for each subnational unit of analysis, which is simply the average of all the estimated adoption date of location cells within that subnational unit. IDW assumes that the surface is driven by the local variation, which can be captured through the neighborhood. This method is part of the deterministic techniques to create a surface of adoption dates. Another class of interpolation techniques, often known as kriging, uses geostatistical properties. Kriging relies on autocorrelation as a function of distance and assumes that the data comes from a stationary stochastic process. Given the terrain variation and boundaries, however, the spread of agricultural adoption does not appear to satisfy this assumption. Pinhasi (2005)