146 THE HISTORY OF MEDIEVAL EUROPE place not only when a man sees it for the first time; but it always makes the same impression upon him, as though he had never beheld it before." At Ravenna in Italy, where the buildings of Justinian's time have remained unaltered, one can study, better even Churches at than at Constantinople and Rome, the graceful Ravenna Byzantine capitals and columns and brilliant mosaics, and the early Christian basilican type of archi- tecture. The church of Sant' Apollinare in Classe, which stands three miles outside the city in a deserted plain where was once the busy Byzantine seaport, and the church of Sant' Apollinare Nuovo in Ravenna itself, are two fine sixth-century specimens of the columnar basilica adapted to Christian use. Both are oblong in ground-plan except for the large semicircular apse which protrudes at one end. Each basilica has at its side a round tower of fortified aspect, which does not, however, form an integral part of the building. Their exteriors are very plain, and the low roofs over the side aisles slant in lean-to fashion against the main body of the church. The beauty is all in the columns, the capitals, and the mosaics of the interior. Before entering the nave one passes through a sort of portico or vestibule extending across the front of the building and known as the narthex. The long central nave is separated from the narrower aisle or corridor on either side by a row of slender columns connected by a series of round arches springing from their graceful capitals. Upon these slender columns and arches rest the walls of the main body of the basilica and also the roof which those walls support. Consequently the walls can neither be thick nor carried to a great height and the roof must be a light one of wood. Windows cut in the walls above the roofs of the side aisles admit light directly to the nave and form the "clear- story" of the basilica. Between these windows there is some space for mosaics. But especially beneath them and just above the arches leading into the side aisles is, on either side of the nave, a frieze or strip of mosaic running the entire length of the interior. Furthermore, the apse in which the
