The chapter sets out the story of the era of agrarian/pastoralist empires (CAPE) in terms of its material conditions and social structures. New materials were hard metals and gunpowder. New sources of energy were wind and animal power. New technologies were the sailing ship, wheeled vehicles, writing, money and paper. Society became much more complex and larger in scale, and developed many new institutions, notable amongst which were human inequality (slavery, patriarchy, economic, monarchy, dynasticism), universal religions, empire, territoriality, sovereignty, trade and diplomacy. This package of material and social conditions proved remarkably stable up to the end of the eighteenth century AD. The core military dynamic of this era was between militarily superior nomadic steppe peoples, and more numerous and wealthier sedentary civilisations.