Introduction

The term “crusades against Christians” (or also “internal crusades”) refers to the relatively little-known but very significant conflicts within Christendom in the Central and Late Middle Ages, which shared some of the mechanisms and characteristics of crusades against Muslims in the Holy Land, including similar temporal and spiritual privileges. These crusades consisted of numerous campaigns, launched against various targets in almost every corner of Latin Christendom. But despite the pervasiveness of crusades against Christians, they remain a comparatively understudied aspect of the crusading movement. Traditionally historians dismissed these projects as aberrations of the “proper” crusades to the Holy Land, and even though in more recent years scholars have recognised the importance of crusades against Christians, studies of them remain largely restricted to specific regions, time periods, or campaigns. This Introduction outlines some key characteristics of crusading against Christians, provides a basic survey of past literature, and presents the main aims and contents of the volume.