This is a revisionary study of Muslims living under Christian rule during the Spanish 'reconquest'. It looks beyond the obvious religious distinctions and delves into the subtleties of identity in the thirteenth-century Crown of Aragon, uncovering a social dynamic in which sectarian differences comprise only one of the many factors in the causal complex of political, economic and cultural reactions. Beginning with the final stage of independent Muslim rule in the Ebro valley region, the book traces the transformation of Islamic society into mudéjar society under Christian domination. This was a case of social evolution in which Muslims, far from being passive victims of foreign colonisation, took an active part in shaping their institutions and experiences as subjects of the Infidel. Using a diverse range of methodological approaches, this book challenges widely held assumptions concerning Christian-Muslim relations in the Middle Ages, and minority-majority relations in general.