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.

In the Middle Ages, ‘chivalry’ was a collective noun referring to mounted and fully armed knights and squires. But in modern English, we use the term for the wider martial and courtly culture of those people, and in particular for the ideals of knighthood which are now associated principally with a romantic vision of elegant and civilised masculinity. Yet these assumptions about knightly ideals are based upon a partial reading of the surviving medieval sources, downplaying the overriding importance of more martial qualities like prowess, courage and the competition for honour, and more importantly constant debate about the norms of medieval aristocratic masculinity

What is ‘heresy’? One answer would be, ‘that which orthodoxy condemns as such’; though we may also wish to consider when conscious dissent invites such a condemnation. The main ‘heresy’ in late medieval England was that usually termed Lollardy, understood to be inspired by the radical theological thought of John Wyclif (1328-1384), which among other things emphasised the overwhelmingly importance of Scripture, and of lay access to Scripture, through vernacular translation. Orthodox repression of heresy began in the late fourteenth century and developed in various ways in the fifteenth. There are small traces of these much wider battles in Chaucer’s oeuvre, but it would be very hard to say quite how he saw them. We might instead see the fluidity of attitude toward aspects of religion in Chaucer as a sign of his times. ‘Dissent’ can encompass more than that which is solidly decried as heresy, and ‘orthodoxy’ can turn out to be more than one mode of religious thought and expression.