From Carolingian times this was
designated the _arch of triumph_, because a cross was suspended from it.

[Illustration: FIG. 8.--S. Apollinare in Classe, Ravenna.]

The conch or semi-dome that covered the apse was always covered with mosaic
pictures, usually paintings of our Lord, either seated or standing, with St
Peter and St Paul, and other apostles and saints, on either hand. The beams
of the roof were sometimes concealed by a flat ceiling, richly carved and
gilt. The altar, standing in the centre of the chord of the apse on a
raised platform reached by flights of steps, was rendered conspicuous by a
lofty canopy supported by marble pillars (_ciborium_, _baldacchino_), from
which depended curtains of the richest materials. Beneath the altar was the
_confessio_, a subterranean chapel, containing the body of the patron
saint, and relics of other holy persons. This was approached by descending
flights of steps from the nave or aisles. The _confessio_ in some cases
reproduced the original place of interment of the patron saint, either in a
catacomb-chapel or in an ordinary grave, and thus formed the sacred nucleus
round which the church arose. We have good examples of this arrangement at
St Peter's and St Paul's at Rome, and S. Apollinare in Classe, Ravenna. It
was copied in the original cathedral of Canterbury. The bishop or
officiating presbyter advanced from his seat in the centre of the
semicircle of the apse to the altar, and celebrated the Eucharist with his
face to the congregation below. At the foot of the altar steps a raised
platform, occupying the upper portion of the nave, formed a choir for the
singers, readers and other inferior clergy. This oblong space was separated
from the aisles and from the western portion of the nave by low marble
walls or railings (_cancelli_). From these walls projected _ambones_ or
pulpits with desks, also of marble, ascended by steps.

The exterior of the basilicas was usually of an extreme plainness. The vast
brick walls were unrelieved by ornament, save occasionally by arcading as
at S. Apollinare in Classe, Ravenna, and had no compensating grace of
outline or beauty of proportion. An exception was made for the entrance
front, which was sometimes covered with plates of marble mosaics or painted
stucco (Old St Peter's, S. Lorenzo). But in spite of any decorations the
external effect of a basilica must always have been heavy and unattractive.
S. Apollinare in Classe at Ravenna