From the twelfth century onwards, sermons concerning the crusade were preached on many different occasions. In the thirteenth century alone, crusades were fought against Muslims in Spain, Africa, the Holy Land and Apulia, the Mongols, non-Christian peoples in the Baltic, heretics in Languedoc, Germany, Italy and the Balkans, Orthodox Christians in Greece and the Hohenstaufen rulers and their supporters in Italy and Germany. These crusades were usually announced by sermons. Propagandists preached in order to recruit participants and collect money for the crusade. Sermons also marked the departure of a crusader or a crusade army. During the campaigns, the clergy accompanying the crusade armies regularly preached sermons in order to sustain the participants' enthusiasm or to give them courage on the eve of a battle or in moments of crisis. Last but not least, sermons concerning the crusade were also preached to those at home in the context of penitentiary processions and prayers in support of crusaders in the field. Indeed, the number of different types of crusade sermons preached at various times in late medieval Europe must have been immense.

Despite this, we are not particularly well informed about what exactly crusade preachers said in their sermons. As with sermons generally, crusade sermons were not the stuff of medieval chronicles or of other narrative accounts of the period. Although these sometimes mention that crusade sermons were preached, they seldom give details about their content. Most of our evidence for crusade preaching comes from manuscript sermon texts preserved in some of the many surviving sermon collections of the middle ages.