The larger medieval churches of France and England, the cathedrals and abbeys, have much in common architecturally, an east–west orientation, an external emphasis on the west front and its doors, long arcaded interiors, high vaulted roofs and windows filled with stained glass. The eastern end of the building contains the Sanctuary and the Altar. The part of the cathedral that shows the greatest diversity and the greatest change is the eastern end. This Article deals with the way the eastern end changed in English and Western European cathedrals from the middle of the 11th century to the close of the 14th century. The development of the eastern end of the cathedral The earliest extended development of the eastern end of the cathedral is that which was first set out in Edward the Confessor's church at Westminster, probably borrowed from the ancient church of St Martin at Tours; in this church, dating probably back to the 10th century, two new elements are found: The carry of the choir aisle round a circular apse so as to provide an occasional aisle round the eastern end of the church Five apsidal chapels, constituting the germ of the chevet, which formed the eastern terminations of the French cathedrals of the 12th and 13th centuries. In England Gloucester Cathedral (1089) also had three chapels, two of which, on the north and south sides of the aisle, still remain; the same is found in Canterbury Cathedral (1096–1107) and Norwich Cathedral (1089–1119), the stern chapel in all three cases having been taken down to make way for the Lady-chapel in Gloucester and Norwich, and the Trinity chapel in Canterbury. The semicircular aisle is said to have existed in the Anglo-Norman cathedral of Winchester, but the eastern end being square, two chapels were arranged filling the north and south ends, and an apsidal chapel projecting beyond the east wall. This semicircular processional aisle with chevet chapels was the favourite plan in the Anglo-Norman cathedrals, and was followed until about the middle of the 12th century, when the English builders in some cases returned to the square east end instead of semicircular apsidal termination. The earliest example of this exists in Romsey Abbey (c, 1130), where the processional crosses behind the presbytery, there being eastern apsidal chapels in the axis of the presbytery aisle and a central rectangular chapel beyond. A similar arrangement is found in Hereford Cathedral, and