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 indepth 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?