In his seminal work on Pharaonic stone masonry, Dieter Arnold (Reference Arnold1991, 3) described the emergence of stone architecture in Egypt as an abrupt occurrence, and the reason for its rapid rise remains poorly understood to this day. The use of stone architectural elements is attested at several funerary and religious sitesFootnote 1 of the Early Dynastic period (c. 3000–2686 bce).Footnote 2 However, these developments foretold little of the dramatic leap manifest in the Step Pyramid complex of Djoser (reigned c. 2686–2667 bce),Footnote 3 a monument of unprecedented scale and fully realized in stone. Despite its many technical ingenuities, the Step Pyramid complex contains many elements evocative of mudbrick architecture, a tradition attested since Naqada II (c. 3500–3200 bce) and well developed by this period (Kemp Reference Kemp, Nicholson and Shaw2000, 78–9).
Mudbrick was the primary material for domestic architecture—including royal palaces—throughout the Pharaonic era (Kemp Reference Kemp, Nicholson and Shaw2000; Spencer Reference Spencer1979). Buildings constructed in mudbrick require consistent maintenance and repairs, an inconvenience that is easily manageable when the structure is inhabited. The adoption of stone in mortuary and religious architecture, on the other hand, is widely recognized to have stemmed from a need for durability. In view of the many examples that remain standing today in Egypt, it is tempting to suggest that this change was intended to create monuments durable for millennia; or, as a later Egyptian term for mortuary temples puts it, ‘mansions of millions of years’ (e.g. Ullmann Reference Ullmann, Wilkinson and Weeks2016). However, as will be demonstrated in this contribution, the early development of stone architecture in Egypt coincided with a wet climate with considerable rainfall. During this period, the threat to mortuary structures constructed in mudbrick would have been far more immediate.
For much of Egypt's prehistory, its climate was drastically different from the characteristic hyperaridity of today (Bunbury Reference Bunbury2019, 14–38). During the Mid Holocene Wet Phase (c. 9500–6000 bp), the region experienced a cooler, wetter climate with monsoonal rain and a ‘Green Sahara’ (Bernhardt et al. Reference Bernhardt, Horton and Stanley2012; Claussen & Gayler Reference Claussen and Gayler1997; Kuper & Kröpelin Reference Kuper and Kröpelin2006). The end of this period saw a gradual aridification throughout North Africa,Footnote 4 although the Egyptian climate remained wetter than its present hyperaridity for much of the Old Kingdom (c. 2686–2160 bce) (Welc & Marks Reference Welc and Marks2014). Iconographic evidence from Lower Egypt appears to corroborate this. In a study of Dynasty 5 (c. 2494–2345 bce) tomb scenes from Saqqara and Abusir, Butzer (Reference Butzer1959) noted depictions of trees and shrubs on sandy and rocky surfaces, which implies a desert–savanna vegetation in the vicinity of Memphis.
More recently, multiple strands of evidence have demonstrated that the early history of Egypt was marked by periods of intense and possibly prolonged rainfall. Owl pellets recovered from tombs at Saqqara suggest that the birds’ diet consisted of damp-loving species such as mice, frogs and toads for much of the Old Kingdom (Pokorný et al. Reference Pokorný, Kočár, Sůvová, Bezděk and Bárta2009). On the other hand, lithological studies at West Saqqara identified two distinct episodes of slope deposits caused by intensive sheet floods—one at c. 4600 bp, around the reign of Djoser, and the other towards the end of the Old Kingdom, around 4200 bp (Welc & Marks Reference Welc and Marks2014). This suggests that the site was occasionally flooded with rainwater, at times causing severe damage to tombs located in the area (Kuraszkiewicz Reference Kuraszkiewicz2013). Local climatic conditions were periodically stabilized between the two episodes, although deposits caused by sheet flows persisted (Welc & Marks Reference Welc and Marks2014, 128–9).
The catastrophic effect of these climatic events on mudbrick architecture was also evident at Giza, starting from Dynasty 4 (c. 2613–2494 bce). At the pyramid town of Heit el-Ghurab, intensive rain led to the liquefaction of mudbrick structures, producing sediments known technically as ‘mudflow’ (Butzer Reference Butzer2001, 3–4). Based on the depth of disaggregated mudbrick residues, Butzer et al. (Reference Butzer, Butzer and Love2013, 3362–3) estimated that this represented a rainfall event of 200–300 mm every four years, in a climatic anomaly that spanned approximately 40–45 years. The flood events caused by intensive rain presented an even greater threat. Due to its unfavourable location across the main channel of a wadi, the town experienced no less than 10 flood events in the same period, often with devastating effects and necessitating significant reconstructions (Butzer et al. Reference Butzer, Butzer and Love2013).
Drying began during the late Old Kingdom in Lower Egypt, as attested by the rapid influx of sand at sites such as Dahshur and Abusir (Bunbury Reference Bunbury2019, 64–5). There was to be a final episode of intense rain towards the end of the Old Kingdom (the aforementioned event at c. 4200 bp), but the hyper-arid conditions that followed are widely regarded to have contributed to the collapse of the centralized state, resulting in the end of the Old Kingdom (Hassan Reference Hassan, Dalfes, Kukla and Weiss1997). At Saqqara, deposition by sheet flow ended and was replaced by aeolian deposit starting c. 4100–4000 bp (Welc & Marks Reference Welc and Marks2014, 129). By the Middle Kingdom, the owls at Saqqara were feeding on aridity-tolerant species such as gerbils and desert toads (Pokorný et al. Reference Pokorný, Kočár, Sůvová, Bezděk and Bárta2009).
Stone architecture in Dynasty 1 (c. 3000–2890 bce)
Although the large-scale use of stone is commonly associated with the royal pyramid complexes of the Old Kingdom, the early development of stone architecture appears to have been driven by the builders of non-royal tombs, particularly those located in the north (La Loggia Reference La Loggia2008). Conversely, stone use was limited at the Dynasty 1 royal necropolis at Umm el-Qa'ab (Abydos, Upper Egypt). The royal tombs typically have brick-lined substructures, and little of their superstructures remains today (O'Connor Reference O'Connor2009, 151). The earliest attestation of stone architecture at the royal necropolis is the granite-paved burial chamber of Den, the fourth king of the dynasty (Arnold Reference Arnold1991, 141). Subsequent Dynasty 1 rulers appear to have abandoned the use of stone in tomb construction (Engel Reference Engel2008, 33).
The royal tombs are associated with a series of mudbrick enclosures located roughly 1.4 km north, in proximity to the floodplain (O'Connor & Adams Reference O'Connor, Adams and Hawass2003, 78). The interior of these enigmatic structures appears to have been left largely as open space, with the exception of a single mudbrick building found in some examples (Bestock Reference Bestock2008, 45–6). Scholarly interpretations tend to focus on the funerary and symbolic aspects of the enclosures, but they also present utilitarian features. All examples dating to Dynasty 1 have a low bench that ran around all four sides of the exterior (Bestock Reference Bestock2008, 45). Mud benches are a common protective measure against water erosion in earthen architecture around the world, and would have protected the enclosure from runoffs and eased repairs (Van Beek & Van Beek Reference Van Beek and Van Beek2008, 469–71). Low, circular features constructed of unshaped limestone blocks are also found at the corners of several enclosures (Bestock Reference Bestock2008, 49). The use of stone in quoining would have increased the strength of the structures, while rounded corners are less likely to be damaged by impact (Correas-Amador Reference Correas-Amador2013, 345; Emery Reference Emery and Wendrich2011, 3; Jaeschke & Friedman Reference Jaeschke, Friedman, Rainer, Rivera and Gandreau2011, 191).
Climate data from Abydos are relatively limited, although this could perhaps be inferred from data obtained at other Upper Egyptian sites. Auger survey at Hierakonpolis (ancient Nekhen), located roughly 150 km south of Abydos, suggests a relatively humid interval during this period (Hoffmann et al. Reference Hoffman, Hamroush and Allen1987). Specifically, Instrumental Neutron Activation Analysis identified a sandy stratum as rainwashed sediment from the Wadi Abul Suffian, which was dated by associated pottery to c. 5200-4500 bp (Hoffmann et al. Reference Hoffman, Hamroush and Allen1987, 10). The auger survey also revealed the mechanism by which the reduction in rainfall following the Mid Holocene Wet Phase led to a loss of vegetation (Bunbury Reference Bunbury2019, 47; Hoffmann et al. Reference Hoffman, Hamroush and Allen1986). Human activities such as tree felling for fuel and building material further destabilized the wadis, resulting in frequent washouts during the Predynastic and Early Dynastic periods (Bunbury Reference Bunbury2019, 50–51).
The city of Nekhen straddled the desert–floodplain ecotone, and much of it was laid directly in the path of the Wadi Abul Suffian (Hoffman et al. Reference Hoffman, Hamroush and Allen1986, 177). A prominent feature of Nekhen was an early templeFootnote 5 consisting of a sand mound enclosed by a roughly circular stone revetmentFootnote 6 (Quibell & Green Reference Quibell and Green1902). During wadi wash events, the stone revetment would probably have provided protection to the mound,Footnote 7 and it is tempting to hypothesize that this would have created an image akin to the primaeval mound emerging from the pre-creation waters. Likewise, the aforementioned enclosures at Abydos are located in proximity to a wadi commonly referred to as the ‘processional valley’ (see Reader Reference Reader2017, 86), although it is unclear to what extent the structures would have been affected during washouts.
The most elaborate private tombs of this period were found at Saqqara in Lower Egypt. These typically consist of brick-lined substructures with a rectangular superstructure (mastaba) located above the burial chambers. Notably, a few of these tombs display a substantial use of stone material. For example, Mastaba 2185, dated to the reign of King Djer (the second king of Dynasty 1) was partially roofed with stone slabs (La Loggia Reference La Loggia2008). The use of stone material for door frames and lintels was also attested in other tombs (Emery Reference Emery1958, 37–46; La Loggia Reference La Loggia2008). Petrographic study indicates that some of the stone material used in these tombs consisted of fine and highly weather-resistant limestone, similar to that later used as casing for Djoser's pyramid (Klemm & Klemm Reference Klemm and Klemm2010, 16–21).
The geology of Saqqara also facilitated the tunnelling of the tombs’ substructure, an important innovation that became popularized in the later part of Dynasty 1 (Dodson & Ikram Reference Dodson and Ikram2008, 138; Reisner Reference Reisner1936, 5). A by-product of this trend was probably the increased availability of stone materials, leading in turn to a growing familiarity with the medium. An innovation associated with this development were stone portcullises, which started to be employed with regularity in Lower Egypt during this period (Clark Reference Clark2016, 239; La Loggia Reference La Loggia2008).
Located across the Nile from Saqqara is Helwan, a vast necropolis with more than 10,000 burials (Saad Reference Saad1969). Although the majority of the burials are modest and made use of perishable construction material, a small number of elite tombs attest to the use of limestone at an unprecedented scale. It is here that we see Egypt's first stone-lined subterranean chambers, some of which were roofed with stone slabs (Arnold Reference Arnold1991, 174; Köhler Reference Köhler2005, 12). Many display considerable technical mastery—one example (Op.1/1 or 40.H.3) had slabs that were shaped with vertical grooves and angled specifically to assist alignment (Köhler Reference Köhler2008, 122). It is estimated that 70–80 tonnes of limestone were employed for the construction of Tomb 40.H.3, with the heaviest block weighing approximately 2.4 tonnes (Köhler Reference Köhler2005, 24). With one possible exception, all stone-cased tombs at Helwan have been dated to Dynasty 1 (Köhler Reference Köhler2008, 119). The abandonment of this form coincided with the rise of the tunnelled burial chamber in Dynasty 2, which created tombs naturally contained within the bedrock (Köhler Reference Köhler2008, 124–8). Some tombs at Helwan also had decorated limestone slabs, often interpreted as predecessors of the false door, which eventually became a key element in Egyptian funerary practice (Köhler & Jones Reference Köhler and Jones2009; Saad Reference Saad1957).
Multiple strands of evidence indicate that rainfall was a considerable issue at Helwan. Auger survey indicates that there was occasional, or possibly seasonal, flow in the wadis while the site was in use (Köhler Reference Köhler2005, 10). Indeed, the arrangement of the larger tombs appears to respect the existing ridges and gullies at the site, and constructions are conspicuously absentFootnote 8 in areas that coincide with local flood channels (Jeffrey & Tavares Reference Jeffreys and Tavares1994, 153). At Wadi Gerawi, about 10 km southeast of Helwan, a dam was constructed during the early Old Kingdom, with the intention of protecting the alluvial plain from flash floods (Arnold Reference Arnold1991, 243–6; Dreyer & Jaritz Reference Dreyer, Jaritz, Garbrecht and Bertram1983). Arnold (Reference Arnold1991, 243–6) estimates that the Sadd el-Kafara dam (as it is known today) would have held up to 600,000 cubic metres of water, although its construction was never completed, having been destroyed by a flood during the process.
Whether or not the adoption of stone material at Helwan is a reaction to the climatic conditions is, of course, a difficult question to answer. As many of the substructures have been disturbed by post-deposition processes, it is unclear if the stone encasements would have rendered the tombs waterproof.Footnote 9 Little remains of the superstructures at Helwan, although it is likely that many tombs had mudbrick structures of the mastaba form, with some surrounded by an enclosure wall (Köhler Reference Köhler2008, 122; Reference Köhler2014, 89). There is some evidence for stone elements on the superstructures,Footnote 10 although their extent is unclear due to poor preservation.
The critical environmental factor for stone construction in Dynasty 1 appears to be the local availability of material.Footnote 11 As noted by Reisner (Reference Reisner1936, 122–3), the prevalence of stone use in the Memphite region is related to local geology, with the limestone stratum often found close to the surface. Moreover, the geological structure of the Saqqara plateau conveniently provides different kinds of material, ranging from compact, fine-grained limestone suitable for construction to calcareous marl (tafl) that can be used as mortar or in tafl bricks (Kuraszkiewicz Reference Kuraszkiewicz2013, 241–2). Meanwhile, the site of Helwan likely benefitted from its proximity to the quarries at Ma'sara and Tura (La Loggia Reference La Loggia2008).Footnote 12 Overall, the evidence from this period suggests that stone use was more prominent in the private tombs in the north than the royal tombs in Abydos. This observation is incongruous with the traditional view that technical development in tomb architecture was led by royal examples and only later imitated by non-royal tombs (Reisner Reference Reisner1936, 6). Such a geographical divide would remain discernible in Dynasty 2, as the location of the royal burials alternated between Saqqara and Abydos.
Stone architecture in Dynasty 2 (c. 2890–2686 bce)
With the move of the royal necropolis to Saqqara at the start of Dynasty 2, many stone elements previously found in the private realm were incorporated into royal mortuary architecture. The passageways that led to the rock-cut tomb of Hotepsekhemwy (the first king of the dynasty) are roofed with limestone blocks and protected by stone portcullises (Dodson & Ikram Reference Dodson and Ikram2008, 140–41). A similar substructure is attested for Ninetjer, although the identification of the other Dynasty 2 royal tombs at Saqqara remains problematic (Dodson & Ikram Reference Dodson and Ikram2008, 141).
For unknown reasons, Peribsen, the sixth king of the dynasty, returned to Abydos for the construction of his tomb. He also abandoned the tunnelled tomb design common at Saqqara, opting instead for a sunk pit burial lined with mudbrick,Footnote 13 which is reminiscent of Dynasty 1 examples at Umm el-Qa'ab (Dodson & Ikram Reference Dodson and Ikram2008, 140–41). The Abydene tomb of Khasekhemwy, his successor, also utilised a sunk pit burial, albeit one that adopted various elements of the Saqqara type (O'Connor Reference O'Connor2009: 157). The burial chamber was lined entirely with limestone blocks, and loose stone slabs found within suggest that it was roofed with stone before being covered by a mud floor (Dreyer Reference Dreyer and Hawass2003, 76; Engel Reference Engel2008, 33).Footnote 14 The chamber was surrounded by a vast network of storage chambers constructed in mudbrick (Dreyer Reference Dreyer and Hawass2003, 76-–7). Little remains of the superstructure, although limestone blocks found at the site indicate that it may have had a stone casing (Dreyer Reference Dreyer and Hawass2003, 76).
Khasekhemwy's tomb represents a giant leap in stone use at the Abydene royal necropolis, but the most significant stone monument of this period is nonetheless found in the north. The enclosure at Gisr el-Mudir, located to the west of Saqqara, covers an area of approximately 615 × 400 m (Mathieson et al. Reference Mathieson, Bettles and Clarke1997, 53).Footnote 15 Constructed in layers of roughly hewn limestone blocks, the enclosure is considered the oldest monumental stone construction in ancient Egypt (Regulski Reference Regulski2009, 226; Van Wetering Reference Van Wetering, Hendrickx, Friedman, Ciałowicz and Chłodnicki2004, 1070). Its construction benefitted from the easily accessible limestone of Saqqara, which occurred conveniently with layers of tafl which were used as mortar (Dickinson Reference Dickinson2014, 134; Mathieson et al. Reference Mathieson, Bettles, Dittmer and Reader1999, 23–4). The dating of the enclosure remains problematic, although recent studies have increasingly favoured a late-Dynasty 2 date, with Khasekhemwy as its likely instigator (Mathieson et al. Reference Mathieson, Bettles and Clarke1997, 53; Regulski Reference Regulski2009, 226).Footnote 16
Khasekhemwy also constructed monumental enclosures at Abydos and Hierakonpolis, although mudbrick was the main material for both.Footnote 17 Assuming that the attribution to Khasekhemwy is correct, the choice of material at Gisr el-Mudir presents another strong example of the geographical divergence in stone use. Indeed, Gisr el-Mudir is often regarded as the stone equivalent to the mudbrick enclosures of Abydos (Mathieson et al. Reference Mathieson, Bettles and Clarke1997, 53). Its crude masonry betrays a lack of familiarity with the new material, while its buttresses and quoining are reminiscent of earthen architecture technique (Dickinson Reference Dickinson2014, 232–3; Spencer Reference Spencer1979, 112–13).
The Step Pyramid complex of Djoser and the mudbrick problem
With the first ruler of the Third Dynasty came the proverbial giant leap in Egyptian stone architecture. Djoser's 15 ha funerary complex was fully realized in stone, consisting of the Step Pyramid (originally constructed as a mastaba, with layers added later in stages) and a series of subsidiary constructions, surrounded by an enclosure rising up to 10.5 m (Firth & Quibell Reference Firth and Quibell1935; Lauer Reference Lauer1936). The suddenness of its emergence is perhaps best illustrated by several architectural elements that are evocative of mudbrick and organic material—the panelled enclosure reminds one of Khasekhemwy's funerary enclosure, while ceiling stones were carved to imitate wooden beams (Arnold Reference Arnold2003, 72; Firth & Quibell Reference Firth and Quibell1935, 12). Small, regular blocks of stones resembling mudbrick were utilised for construction,Footnote 18 and quoining remained a weak point (Arnold Reference Arnold1991, 120–22, 128).
The core of the pyramid was constructed using less durable limestone, probably quarried in the immediate vicinity, whereas its casing consists of more weather-resistant limestone (Klemm & Klemm Reference Klemm and Klemm2001, 638–9; Reference Klemm and Klemm2010, 14–16). The rationale for this may perhaps be related to the local climate condition around the time of the Step Pyramid's construction. Based on research on geomorphology and geological exposure at West Saqqara, Trzciński et al. (Reference Trzciński, Kuraszkiewicz and Welc2010) demonstrate that the period leading up to Djoser's reign coincided with a transition to a cooler and wetter climate, one characterized by frequent and moderate rain. More details were provided by Welc's (Reference Welc2011) lithological study of the quarry located on the west of the Step Pyramid, which was a likely source of material for Djoser's complex. The oldest layer of deposit (L1) consists of loose rock debris and mudbrick fragments, as well as Dynasty 3 pottery sherds (Welc Reference Welc2011, 283–5). Building material and pottery recovered from the two overlying layers (L2 and L3) indicate that both are contemporary with the period of the Step Pyramid's construction (Welc Reference Welc2011, 285–6). These layers contain deposits caused by flowing water of considerable kinetic force, which suggest frequent flooding (Welc Reference Welc2011, 299). In particular, the strongly cemented structure of L3 was caused by cyclical watering of the layers and intensive evaporation; while the high Fe3+ content indicates intensive weathering in a warm and humid environment (Trzciński et al. Reference Trzciński, Kuraszkiewicz and Welc2010, 204). The intensity of rainfall began to lessen later in the Third Dynasty, with Layer L5 no longer as strongly cemented as L3 (Trzciński Reference Trzciński, Kuraszkiewicz and Welc2010, 204; Welc & Marks Reference Welc and Marks2014).
Taken together, these data suggest that the local climate was considerably wetter around the reign of Djoser than it is today. They also present the intriguing possibility that the great trench that surrounds the Step Pyramid complex (commonly referred to as the ‘dry moat’)Footnote 19 would occasionally have been filled with water following downpours.Footnote 20 If proved true, this might explain why it was not until the reign of Userkaf and Unas (Dynasty 5) that the moat was ‘violated’ by new constructions. The onset of more arid conditions around the end of Dynasty 4, as demonstrated by the sand intrusion at Dahshur (Alexanian et al. Reference Alexanian, Bebermeier and Blaschta2012; Bunbury Reference Bunbury2019, 64–5), may have made the moat area more suitable for new constructions.
If the use of stone material at the Step Pyramid was precipitated in part by the prevailing climate conditions, this could explain why many of its architectural elements appear to be hastily adopted from mudbrick architecture. At the same time, it must be considered that these changes in climate would also have impacted the production of mudbrick. Despite the common association of mudbrick as being easily manufactured, modern examples suggest that the process is highly vulnerable to rain (Van Beek & Van Beek Reference Van Beek and Van Beek2008, 153–4). Caroline Simpson's (pers. comm., March 2020) work on modern architecture at Qurna, Upper EgyptFootnote 21 suggests that even though mudbrick construction occurred year-round, drying is typically quicker in the summer. Moreover, the time required for drying mudbrick also varies depending on region, with longer periods required in areas of high humidity such as the Nile Delta (Nicholas Warner pers. comm., May 2020).
Although these modern examples suggest that mudbrick production was not subject to the strict seasonality that we know to constrain pottery production in Egypt,Footnote 22 the time required for mudbrick to dry could be incongruous with monumental constructions. Morgenstein and Redmount (Reference Morgenstein and Redmount1998, 130) suggest that this process should preferably take ‘an entire summer’, whereas Ormeling (Reference Ormeling, Midant-Reynes, Tristant and Ryan2017) proposes a drying time of four months for the Dynasty 1 mastabas at Saqqara.Footnote 23 Mudbrick requires a drying area that is level, smooth and free from run-off water—in instances where vast numbers of bricks are required, the drying area required can be very large (Van Beek & Van Beek Reference Van Beek and Van Beek2008, 153–4). Constructing on a monumental scale also adds to maintenance issues, as the interior of the wall needs to be dried or cured to prevent cracking and shrinking (Van Beek & Van Beek Reference Van Beek and Van Beek2008, 264). The mudbrick walls at the Temple of Karnak, for example, contained a series of air passages that aided this process (Clarke & Engelbach Reference Clarke and Engelbach1930, 210).
Geographical variations in raw material could also have contributed to the favouring of mudbrick in the south. Correas-Amador (Reference Correas-Amador2013, 188) posits that the use of marl clay in Middle Egypt would have produced more durable mudbrick than that of the Delta, which was predominantly made of alluvial mud. Modern mudbrick structures in Egypt retain certain geographic variations, one of which is the prevalence of unroofed rooms in the south, which is thought to be less common in the north due to the higher frequency of rain (Correas-Amador & Simpson Reference Correas-Amador, Simpson, Mileto, Vegas López-Manzanares, García-Soriano and Cristini2017).
There are other factors that could have restricted the large-scale production of mudbricks. Theoretically, the construction of mudbrick monuments allows the employment of a tax-brick system (Dickinson Reference Dickinson2014, 228), but this would have presented problems of standardization. Evidence from ancient Egypt suggests that substantial diversity in mudbrick composition can often be found at the same site, sometimes even within a single structure (Morgenstein & Redmount Reference Morgenstein and Redmount1998, 131).Footnote 24 Such variability in quality, however, would have been less tolerable for monuments of the scale and repute of Djoser's complex.
The relevance of these factors to Dynasties 1–3 remains to be substantiated, but they illustrate the variety of challenges involved in the use of mudbrick in monumental architecture. Although it was constructed in stages, it is worth noting that Djoser's funerary complex demanded a quantity of building material that was, at the time, unattested in Egyptian history. Rough estimates suggest that the pyramid itself required approximately ten times the volume of material used for Khasekhemwy's enclosures at Abydos.Footnote 25 If the construction of royal monuments is largely dependent on seasonal labour (as is generally assumed),Footnote 26 the window for mudbrick production would have been fairly limited. During the inundation,Footnote 27 when the supply of labour would presumably have been the most plentiful, the humidity of the Delta would have impaired the drying process, and access to alluvial soil would have been restricted. For a monument of the Step Pyramid's scale, building in stone might have been more of a necessity than a luxury.
Some additional considerations
The aforementioned climate data suggest that some mudbrick funerary structures would have deteriorated considerably within decades—or even years—after their completion. For the ancient Egyptians who witnessed this, the natural reaction would have been a longing for tombs constructed in more durable material. However, in earlier periods, where much of tomb building took place following the owner's death, this would have been difficult to attain. Even in Egypt, veneration of the dead was not detached from prosaic and earthly constraints. Its history is littered with constructions that were interrupted by the owners’ untimely death, many of which were hastily completed in inferior material or abandoned completely. This principal–agent problem was a stumbling block to innovation and investment in the funerary realm.
A turning point in the microeconomics of tomb construction took place during the reign of Den, with the introduction of the subterranean tomb with an entrance stairway (Engel Reference Engel2008, 33; Reisner Reference Reisner1936, 57). This enabled the construction of the tomb, including its superstructure, to be completed during the lifetime of the owner. Originally a product of filial piety, the preparation of tombs became a matter of self-interest, a far more potent source of human motivation.Footnote 28 This change in economic behaviour played a catalysing role in enabling the monuments of superhuman scale in later dynasties.
Stone constructions became the norm for royal tombs that followed Djoser, although the reliance on local material persisted. For example, the subsequent move of royal burials away from Saqqara was likely tied to the exhaustion of high-quality casing stone by Djoser's construction project (Klemm & Klemm Reference Klemm and Klemm2010, 47). Through a combination of petrographic and geochemical methods, Klemm and Klemm (Reference Klemm and Klemm2010, 159) demonstrate that the majority of Old Kingdom pyramids derived their core material from the close vicinity.Footnote 29 The location of the pyramids was thus determined mainly by proximity to quarry sites, which outweighed political factors such as their distance to the capital (Klemm & Klemm Reference Klemm and Klemm2010, 159). Furthermore, the choice of the site was also connected to geomorphological factors, such as the suitability of bedrock (Bárta Reference Bárta2005).
The so-called provincial pyramids, a series of monuments located close to major settlements away from the Delta, were constructed using a variety of material derived from their respective locales (Cwiek Reference Cwiek1998, 45; Marouard & Papazian Reference Marouard and Papazian2012, 8). Meanwhile, the unconventional location of the brick pyramid at Abu Roash was likely to have been motivated by its proximity to the floodplain, which would have enabled easy access to raw material (Clark Reference Clark2016, 62; Dodson Reference Dodson1998, 36). These geographical variations in the choice of material have a direct impact on the survival of monuments, and may have contributed to the apparent lack of ‘formal’ temple architecture at provincial sites during the Early Dynastic period and the Old Kingdom (Kemp Reference Kemp1989, 65–83; Reference Kemp2006, 111–35).Footnote 30
Wet climatic conditions persisted during Dynasty 4, and their dramatic effect is well documented at the valley temple of Menkaure.Footnote 31 The structure, which was completed in mudbrick following Menkaure's untimely death, was soon devastated by discharged rainwater due to its unfavourable topographic position (Reisner Reference Reisner1931, 44–5). At Heit el-Ghurab, the workmen's village associated with Menkaure's Pyramid, the same precipitation anomaly led to some ten flood events in less than five decades (Butzer et al. Reference Butzer, Butzer and Love2013). Of particular interest to this discussion are the contemporary responses to these climate events. At Heit el-Ghurab, a 200 m stone wall known today as the ‘Wall of the Crow’ was constructed to protect the town from flood damage (Lehner Reference Lehner2010; Lehner et al. Reference Lehner, Kamel and Tavares2006, 21–30). Meanwhile, Menkaure's valley temple underwent multiple reconstructions, and a rubble embankment was added along the northern and western walls of the temple in Dynasty 6 (Reisner Reference Reisner1931, 44–8).
It should be noted that these examples represent climate events of exceptional magnitude—in particular, the liquefaction of mudbrick that took place at Heit el-Ghurab would have required intense and prolonged rainfall (Butzer et al. Reference Butzer, Butzer and Love2013, 3363–4). For much of the Early Dynastic period, flood and wadi wash events would have posed a more immediate threat for sites located in the Nile Valley. During these occurrences, enclosures such as those found at the royal funerary structures at Hierakonpolis and Abydos may have provided a degree of protection. Visually, the protective function of these structures is perhaps best appreciated through the miniature baladi tombs attested in the Memphite region as well as provincial sites,Footnote 32 many of which include a small mound surrounded by a stone enclosure (Fig. 1: Lehner & Hawass Reference Lehner and Hawass2017, 78). Examining the royal enclosures from a utilitarian view will aid our understanding of the funerary landscape, and need not preclude additional symbolic and cultic functions.
Figure 1. A baladi tomb from the Workers’ Cemetery at Giza, consisting of a small mud-brick mound and a stone enclosure. (Photograph: © Mark Lehner, from Lehner & Hawass Reference Lehner and Hawass2017.)
Several other aspects of funerary architecture of this period could also have contributed to their resilience. Elite and royal tombs located on plateaux would have allowed rainwater to drain away from the structures, minimizing the ill-effects of surface runoff. Oftentimes, architectural features that contributed to the security of the tomb would likewise have improved its durability under wet climatic conditions. These include the use of subterranean burials that are sealed by portcullis stones, which could have prevented the ingress of rainwater (Reisner Reference Reisner1942, 171).Footnote 33 The introduction of solid-filled mastabas in the Early Dynastic period (Spencer Reference Spencer1979, 24–5, 128) is typically viewed as a measure to prevent access to the substructure, although it would also have contributed to the integrity of the superstructure, which was often constructed in mudbrick.Footnote 34
Conclusions
Much attention has been devoted to the socio-economic and religious factors that contributed to the rise of stone architecture in Egypt. This contribution hopes to demonstrate that more consideration should be given to the climatic and geological conditions that facilitated—and perhaps accelerated—the transition to stone construction. For much of the First Dynasty, this development appears to have been driven by innovations in the private realm, a phenomenon that contradicts traditional views of royal power. Similarly, the extent of stone use in the Dynasty 2 royal tombs appears to have fluctuated as their location alternated between Saqqara and Abydos, although their poor state of preservation does not allow for systematic comparison. Even as stone architecture underwent rapid development in the Old Kingdom, the royal and provincial pyramids continued to be heavily reliant on the use of local material.
The threat of rain to mudbrick structures is twofold—runoff provides an immediate danger to those located in unfavourable terrain, while direct rain damage causes the breakdown of structures. The construction of enclosures—the most prominent examples being the royal enclosures at Abydos—would have mitigated the effects of runoff, albeit without addressing the latter issue. During periods of intensive rain, as attested by the various local climate data, mudbrick funerary structures would have been visibly damaged in the generations following their completion. Such observations, coupled with the ability to complete tomb constructions in one's lifetime, would have generated strong incentives to utilize more durable material.
The adoption of stone material may also have been made easier by climatic conditions in Lower Egypt, which would have affected the large-scale production of mudbrick. The time and conditions required for drying mudbrick, access to alluvial soil, as well as the availability of seasonal labour were all limiting factors that might have made the material non-conducive for monumental construction. If the use of a new construction material was necessitated in part by environmental factors, it would explain the seemingly precipitous adoption of stone at Gisr el-Mudir and Djoser's Step Pyramid, both of which display techniques more suited to mudbrick architecture.
The vast majority of environmental data presented in this article originate from sites associated with royal monuments of the Old Kingdom. A wider range of environmental data, particularly those specific to the Early Dynastic period, will provide a more well-rounded view of the period in question. It must also be stressed that the best reflections of human response to climate are likely to be found on mudbrick constructions, in spite of the obvious difficulty in archaeological recovery. More discoveries in these areas will allow the hypotheses in this article to be put to the test.
Acknowledgements
I am grateful to Katja Goebs for her insightful comments on this article and for improving its prose. Gabriela Lichtblau provided valuable feedback on a draft version. I owe a debt of gratitude to CAJ editor John Robb and the anonymous reviewers for their constructive comments. Special thanks are also due to Maria Correas-Amador, Carmen Jung, Christiana Köhler, Angela La Loggia, Caroline Simpson, Kate Spence and Nicholas Warner for answering questions that arose during the research process. All remaining errors are mine.
