Warfare did not evolve in a linear fashion. This is most obvious on the physical level: the weapons and armies of polities across time and space have fluctuated in sophistication, so that early European medieval armies had more in common with ancient Israelite or Greek contingents than with the Roman war machinery, and, up to the nineteenth century or even the twentieth, raiding warfare in some parts of Africa or the islands of south-east Asia was akin to patterns of pre-Columbian warfare in the Americas, prehistoric warfare in Europe and ghazis and booty expeditions in Europe and around the Mediterranean. Where warfare’s aims went beyond mere raiding, for much of world history, the paucity or even absence of relevant sources has made it difficult to reconstruct political–strategic aims. We also encounter vast varieties conditioned in part by hard factors such as climate, geography and resources. We have encountered and possibly not always avoided the danger of squeezing cultural differences into a Procrustean bed of Western concepts and languages. Yet some striking patterns have emerged. Not only Indo-European cultures, but also Mongols and Chinese, came up with a strategic aim of establishing a universal monarchy, or defending against the imposition of such an overlordship. The forming of alliances for common strategic purposes and the defence of allies or clients is another widespread pattern, strategic co-operation counterbalancing long-term hostilities. The distinction between client states and allies was often blurred. Non-kinetic tools of strategy were also employed widely, from giving gifts, to tribute payments (again a distinction often difficult to make), to marriages to confirm peace treaties or cement alliances. And most cultures seem to have had some rules or code of honour with regard to the conduct of war which in many contexts imposed limits on the pursuit of strategic aims.