The Popes and the Baltic Crusades examines the extension of the crusading idea from the Holy Land to the Baltic region. Highlighting the interplay between canon law, missionary ideas and politics, it shows how papal policy on the campaigns against the pagan peoples of north-eastern Europe developed from Pope Eugenius III’s proclamation of a crusade against the Slavs in 1147 to the end of Innocent IV’s pontificate in 1254. It also discusses the interaction between Rome and the princes and bishops of the Baltic region and demonstrates how these local leaders influenced papal crusading policy. The volume shows the variety of the crusading movement of the central Middle Ages and offers a contribution to the ongoing debate about the nature and definition of crusading.