TWILIGHT AND DAWN PROM THE <5TH TO THE IOTH CENTURY scholce, or the private halls in large houses and palaces (for instance, that of the Flavian emperors on the Palatine (fig. 3))—smaller apsed rooms, which may indeed have been used for private worship by Christians. But since 1917 we know of a much more direct connection between Christian and Pagan religious architecture. The so-called Basilica of Porta Maggiore (fig. 4) is a little subterranean building of only about forty feet length. With its nave and aisles, its piers and apse it looks exactly like a Christian chapel Stucco reliefs reveal that it was the meeting-place of one of the many mystical sects which had come to Rome from the East, before and after the advent of die sect of the Christians. It is attributed to the ist century A.D. Considering the close dependence of Early Christian thought on that of the other oriental religions believing in a saviour, in sacrifice and re-birth, the basilica of Porta Maggiore is the most convincing single source of Early Christian architecture yet found. During the 4th century Constantine and his successors built vast basilicas in East and West; by the 5th century Christian churches existed everywhere—even in England (Silchcster). Most of them are varieties of the basilican plan. An exception were baptisteries and memorials or mausoleum chapels for which, on a Roman precedent, centrally planned buildings were preferred. On a large scale central planning was developed chiefly in Byzantium itself. It culminated in Justinian's two large churches, St. Scrgius and Bacchus and then St, Sophia (532-37). On Italian soil a reflection of these, and a res- plendent one indeed, is found at Ravenna, which after the fall of the Ostrogoths had become the capital of Byzantine Italy. S, Vitalc was built by the same Justinian and completed in 547 (pL IV and fig. 5). It is an octagon with a two-storied octagonal ambulatory, a chancel and apse added at the east end, and at the west end a narthcx or ante-* room for the congregation to collect before entering the House of God. The spatial motif that determines the character of the room, a motif of purely aesthetic, Le. no functional purpose, is the use of the niches into which the central octagon expands. As these niches arc not enclosed by walls, but open out with arcades into the ambulatories on the ground floor and the first floor, no clear distinction exists between the two main parts of the building. The central space flows into the ambulatory, and the ambulatory becomes a senseless shape if looked at as an independent unit. The same sensation of uncertainty, of a dreamlike; floating, is created, where solid walls remain, by the 6