The Christian domination of the Ebro was not achieved in any profound sense with the surrender of the region in the late eleventh and early twelfth centuries. On the contrary, the military conquest initiated a process of social evolution and cultural transformation which continued until the eventual expulsion of the moriscos in the seventeenth century. The initial period of occupation was marked by a willingness on the part of the Christian powers to extend far-ranging autonomy to the conquered peoples, who became tributaries, and as the demographic balance shifted in the Christians' favor, and the Crown developed more sophisticated legal and administrative apparatus, the Muslims were gradually drawn into “Occidental” institutions as participants and subjects. Thus, the Islamic society of the region was not destroyed by the conquest, but had re-emerged as a mudéjar society by the thirteenth century.