EARLY CHRISTIAN ARCHITECTURE. 187 fine mosaics representing the Baptism of Christ, and altars with the open books of the Apostles. It resembles the Temple at Spalato (p. 130), but with arcades instead of horizontal architraves. TOMBS. S. Constanza, Rome (a.d. 330), was erected by Constantine as a tomb for his daughter, but was converted into a church in 1256. It has a dome, 35 feet in diameter, supported on twelve pairs of coupled granite columns. The Tomb of Galla Placidia, Ravenna (a.d. 420) (No. 73 h, J, k), is exceptional, as it is cruciform in plan, instead of the usual circular form. It is 35 feet by 30 feet internally, and has a raised lantern at the crossing, pierced with four windows. It is domed by a portion of a sphere, and is one of the few examples in which the pendentives and dome are portions of one hemisphere (No. 79 h). Each of the arms of the cross contains a sarcophagus, and the interior is remarkable, as it retains all its ancient poly- chromatic decoration in mosaics. The Tomb of Theodoric, Ravenna (a.d. 530) (No. 73 c, D, E, F, g), is two stories in height, the lower story being a decagon, 45 feet in diameter externally, and containing a cruciform crypt. Traces remain of an external arcade round the upper portion, standing on the decagonal basement. The roof consists of one slab of stone, hollowed out in the form of a flat dome, 35 feet in diameter, and round the edge of this block are stone handles, origin- ally used to place this immense covering in position. The ashes of the founder were placed in an urn on the top of the covering. Syria has a number of interesting monuments erected between the third and eighth centuries, notably those by Constantine— the Church of the Nativity, Bethlehem, the Church of the Ascension, Jerusalem, and the octagonal Church of the Holy Sepulchre on the site of the Temple of Solomon, also at Jerusalem. The Syrian type appears soon to have broken away from Roman influence, due largely to the abundance of hard stone, the absence of brick, and the distance from Rome. Piers were used instead of columns, and roofs formed of stone slabs were usual. A favourite plan was a circle placed in a square, the angles being filled with niches, as in the Churches at Bozrah and Ezra. Such are considered to be prototypes of later Byzantine churches of the type of S. Sergius, Constantinople (No. 79 e, f, g), and S. Vitale, Ravenna (No. 83 c, d). Salonica possesses important examples, notably the domical Church of S. George. In Asia Minor, as at Ancyra, Pergamus, and Hierapolis, and in Egypt and Algiers are many examples of basilican and circular buildings of the Early Christian period.
