Under Constantine, Christian churches of larger dimensions were constructed; marble decorations and a profusion of columns were common. The five aisles still predominated, the Athanasians not having yet succeeded in establishing the Trinitarian doctrine. St. Peter’s at Rome (rebuilt in the 16th century); Sta. Croce at Jerusalem, and the Church of Sta. Maria at Bethlehem, built by Helena, the wife of Constantine, were splendid specimens of the pure early Christian style. The transept before the raised apsis was an innovation. The central aisle (the nave) rises in independent loftiness. The galleries are dispensed with, as the dimensions of the building are considerably increased. Light is admitted through windows in the lofty central aisle. The lines all tend towards the altar, and the high tribune. The nave is separated from the transept by a lofty arch supported by pillars. The transept is provided with broad windows, throwing the greatest amount of light on the altar, by which means a sublime effect is attained. St. Peter’s at Rome, and Sta. Maria at Bethlehem, are provided with cross-beams, which do not accord with the superstructure, which is too heavy. Before these churches, in a court-yard, stood the fountain. These fountains were common to all the Indian, Egyptian, and Hebrew temples, because the _sanctity of water_ was recognised by all the religious sects of the Southeast. _San Paolo fuori le mura_ belonged to this class of churches. It was constructed by Theodosius and Honorius. ‘The mighty apsis, about eighty feet in breadth, is increased in effect by a lofty transept, which stretches in front of it, across the whole nave. The body of the church has five aisles. Eighty granite columns, connected by circular arches, rise in four rows in order to divide the aisles, and to support the upper wall of the central aisle, and the framework of the roof. The main aisle opens into the transept with a broad and lofty triumphal arch, which rests on two colossal columns. A splendid atrium, surrounded with colonnades, was added to the front, completing the plan of this basilica.’ The high walls above the central isle fulfilled a double purpose: they vividly expressed an expanding tendency upwards, and filled the soul with the idea of the infinite. This tendency was still more strongly expressed in ecclesiastical or Gothic architecture. Scenes from the life of Christ and his disciples were painted, and, in imitation of Roman decoration, gilded panels and marble pavings were freely used. After the fourth century the five aisles were gradually abandoned, and only three were used, symbolic of the Trinity. We have here a kind of Indian or rather Buddhistic renaissance.