altar.]

Sec. 8. Of the two types of plan, which can be studied so satisfactorily at
Ravenna, the ordinary basilican type is the more convenient. The long
nave provides the necessary accommodation for worshippers, the raised
apse gives a theatre for the performance of service within view of
everybody, the aisles facilitate the going and coming of the
congregation, and prevent over-crowding. The centralised plan provides,
it is true, a large central area conveniently near the altar; but the
provision of a chancel or altar-space necessitates the grafting on the
plan of a feature borrowed from the ordinary basilica, which, as at San
Vitale, breaks the symmetry of the design. At Santa Sophia, the
basilican chancel forms an indissoluble part of a centralised plan; but
this feat is beyond the reach of an ordinary architect. Even at San
Vitale the planning is highly complicated, and must be due to an
architect of some genius. In addition to complications of design, the
centralised plan raised questions of roofing which did not trouble the
builders of the long wooden-roofed basilicas. The vaulted half-dome of
the basilican apse was a simple matter, compared with the mighty dome of
Santa Sophia and its cluster of abutting half-domes. It was in the
centralised churches, with their domed vaults and the groined vaults of
their aisles, that the history of medieval vaulting began. But, even
when medieval masons had learned to regard the vaulting of their
churches as the controlling principle of their art, they left the
centralised plan almost entirely alone, and applied what it had taught
them to the work of roofing basilicas with vaults of stone. We shall
trace the influence of the centralised church as we proceed; but the
influence of the basilica will be found to predominate in the history of
medieval planning.

Sec. 9. In England, as in other portions of the Roman empire, we might
naturally expect to find the basilican plan applied to the earliest
Christian churches. The foundations of a small Romano-British basilican
church have been discovered at Silchester in Hampshire. The apse, as in
the Roman basilicas, was at the west end. The nave had aisles, which, at
the end nearest the apse, broadened out into two transept-like
projections. The entrance front of the church was covered by a
_narthex_, the whole width of nave and aisles. This feature, as has been
shown, is of eastern rather than of Roman origin; while the projections
a