The eastern churches remained lively in the eleventh and twelfth centuries, whatever the vicissitudes they experienced. The Byzantine emperors, in the eleventh century, continued to operate within the tradition of the elimination of heresy. The great churches, which had been turned into mosques became cathedrals once more; the number of churches grew, Christian populations were attracted into the reconquered lands. The Latins dispossessed the Greek prelates of their cathedrals and the Greek communities of their pre-eminent position in the sanctuaries. However, they very quickly adapted to the situation of the eastern churches, and made space for each alongside the Latin church, refraining from the harassment which the Byzantines had inflicted on other confessions. The Franks adopted the devotions of the eastern Christians, and the monasteries of each confession were able to prosper. The Latin church of the Maghreb continued to use Latin as its liturgical language and in funerary inscriptions, although the Christians increasingly used Arabic.

This chapter discusses the structure of the Latin church during the mid-eleventh century, and deals with the secular church, the church of popes, bishops, lesser clergy and laity. It focuses on the structure of the mid-eleventh century church through evidence which is characteristic of the period. The structure is illustrated by examples from the liturgy and from the older canon law. The Litany that it contained began by invoking Christ himself, as saviour of the world. In the south, the organisation and structure of the church were even less settled, largely on account of political factors such as the vicissitudes of the Lombard principalities, the Norman incursions and settlement, and the existence until the fall of Bari in 1071 of a Byzantine catapanate. The diocesan and provincial structure of the French church in general followed the organisation of Roman Gaul. All over Latin Christendom, leading sees were vying to claim their place in the ecclesiastical structure.