Eric Böhme analyses two processes of conquest which are generally considered prime examples of the expansion of Latin-Christian powers into the Islamicate Mediterranean. The Norman conquest of Sicily 1061–1091 put a close to more than two hundred years of Muslim rule over the island. Two centuries later, the Catalan-Aragonese conquest of eastern al-Andalus (c. 1229–1245) and its transformation into the Kingdom of Valencia constituted a major advance in the Christian expansion on the Iberian Peninsula. The striking parallels between both changes of rulership are now analysed in-depth for the first time. At the centre of the analysis is the perspective of the conquered Muslim communities: With what motivation and strategies did they participate in processes of interaction and negotiation with the new rulers and other immigrant groups?