creen which existed, for example, in old St
Peter's at Rome; the apse takes the place of the _tablinum_, where the
most sacred relics of family life were preserved; and the transept,
which is found in some of the early Roman basilican plans, represents
the _alae_, or transverse space, which existed between the _tablinum_
and the main body of the hall. But these close analogies are the result
of an assumption by no means certain. It is always probable that the
basilican plan had its origin in a plan originally aisleless. Some,
intent on its religious source, explain it as a development of the plan
of the Jewish synagogue. Others, regarding assemblies of Christians for
public worship as, in their essence, meetings of persons associated in
common brotherhood, have derived the basilica directly from the
aisleless _scholae_ which were the meeting-places of the various
confraternities or _collegia_ of ancient Rome. In these there is an apse
at one end of the building; and, if we imagine aisles added by the
piercing of the walls with rows of arches and columns, we have at once
the essential features of the basilican plan. Each theory has its
attractions and its difficulties; and to none is it possible to give
unqualified adherence. It may be stated, as a tentative conclusion, that
the basilican plan probably had its origin in an aisleless form of
building, and thus pursued a course directly opposite to the development
of the secular basilica. But it seems clear that, in many details of the
plan, especially as we see it in Rome, the peristyled hall was kept in
mind; while in two features, the arrangement of the apse and the
occasional appearance of galleries above the aisles, the secular
basilica was taken into consideration. The policy of the early Christian
Church, when its services were sanctioned by the state, was to adapt
existing and familiar forms where they could be suitably reproduced.

[Illustration: Fig. 1. Plan of old St Peter's: (1) _atrium_ or
fore-court; (2) nave with double aisles; (3) site of screen-colonnade;
(4, 4) transepts; (5) apse with crypt below.]

Sec. 4. The plan of the old basilica of St Peter at Rome, founded by
Constantine the Great, and destroyed early in the sixteenth century to
make way for the present church, explains the principal features of the
basilican plan in its developed state. (1) In common with other early
basilicas in Rome, and in other parts of western Europe, the entrance
was at t