Strategy is a not a word not often used in connection with early medieval warfare ,which is often seen as mere feud or the gathering of loot. This was strongly reinforced by the widespread attitude that military history was a fit subject only for military academies. Only recently has it been recognised that war in this period was the subject of thought, care and calculation. Moreover, early medieval sources are relatively scarce and often pose difficulties of interpretation. And armies had no continuous institutional life of the kind we associate with the formation of strategic ideas. Nor were kings able to impose a monopoly of violence on their followers, for early medieval states were fragile and highly dependent upon the accidents of individual ability. The armies which were gathered were not unitary, but assemblages of diverse elements whose political relation to the sovereign was problematic. But although writing about strategy poses challenges, it is evident that military commanders in this period were not mere bloodthirsty brutes. An army, even a small one, represented a huge financial and political investment whose raising could only be justified by some substantial purpose. But the nature of medieval strategy was conditioned by the political structures which created it. A world where dynastic continuity and political stability were closely intertwined, and where kings were rulers of peoples rather than territories, gave birth to a very different kind of strategic outlook from our own.

Europe across the period from 1000–1500 was characterised by a multiplicity of polities, but the majority were unified by membership of the Catholic Church. Indeed Latin Christendom (those polities that recognised papal authority and followed the Latin liturgy) doubled in size by the end of the twelfth century, as frontiers were pushed forward in the Holy Land, Sicily, the Iberian peninsula and the Baltic. This was generally achieved by extraordinary multi-polity coalitions loosely under the direction of the papacy, which confronted enemies of another faith and culture who seemed to present a military and existential threat to Christendom itself. Inter-polity conflict was nevertheless waged within Latin Christendom throughout the period, and especially after the collapse of Latin power in the Holy Land in 1291. As rulers focused more attention on nearby adversaries, they increasingly raised armies by contract for pay, aided by systems of credit, enabling the professionalisation of armies, to a limited extent. Meanwhile, throughout the period, securing divine support was considered important as military means in achieving strategic goals. The strategy and means of political–military elites are revealed through an increasing abundance of sources, notably chronicles and, particularly from the turn of the thirteenth century, an abundance of government records.