1. I will sing unto the Lord,

2. for He hath triumphed gloriously;

3. the horse and his rider

4. hath He thrown into the sea.

5. (Exodus 15:1)

The formation of states, understood as relatively cohesive organizations with the capacity to project power beyond their immediate geographical surroundings, generally lagged behind the introduction of complex economic technologies (from the fishing boat to the domestication of animals) and the emergence of territorial inequalities for a simple reason. The scale and scope of political power was contingent on the kind of military technologies available to political rulers. As pointed out at the end of Chapter 3, human communities only witnessed the emergence of centralized political institutions after war technologies became sophisticated enough – at around 3000 BC or five millennia after the domestication of plants and animals. Moreover, the type of state (from “self-governing” communities to monarchical or dictatorial regimes) also depended on the military or power ratio between looters and producers. As military technologies benefited the former, that is, as bandits’ comparative advantage at waging war increased and as producers’ opportunity costs rose, monarchies became more widespread and horizontal polities or republican compacts less frequent.

Testing the impact of war technologies on political institutions is empirically challenging. War technologies can be roughly classified into two different categories: types of weapons employed in the battlefield and organization of the army (including the kinds of tactical strategies deployed in the conduct of war operations). Both types of war technologies are ultimately linked to each other. For example, relying on horses and horse chariots leads to (or at least facilitates) the development of a strong cavalry and the use of highly mobile units to harass the enemy. Here, however, I treat them as separate types of instruments of war making and then focus on the development of specific weapons (or, more precisely, on the introduction of particular materials to make them) to examine the consequences of warfare on political institutions for three reasons.