aring upon architectural
questions) remain in the Catacombs, it is chiefly for their paintings
that the touching records of the past which have been preserved to us
in these secluded excavations should be studied. Early in the fourth
century Constantine the Great became Emperor, and in the course of his
reign (from A.D. 312 to 337) he recognised Christianity, and made it
the religion of the State. It then, of course, became requisite to
provide places of public worship. Probably the Christians would have
been, in many cases, reluctant to make use of heathen temples, and few
temples, if any, were adapted to the assembling of a large
congregation. But the large halls of the baths and the basilicas were
free from associations of an objectionable character, and well fitted
for large assemblages of worshippers. These and other such places were
accordingly, in the first instance, employed as Christian churches.
The basilica, however, became the model which, at least in Italy, was
followed, to the exclusion of all others, when new buildings were
erected for the purpose of Christian worship; and during the fourth
century, and several succeeding ones, the churches of the West were
all of the basilica type. What occurred at Constantinople, the seat of
the Eastern Empire and the centre of the Eastern Church, will be
considered presently.

There is probably no basilica actually standing which was built during
the reign of Constantine, or near his time; but there are several
basilica churches in Rome, such as that of San Clemente, which were
founded near his time, and which, though they have been partially or
wholly rebuilt, exhibit what is believed to be the ancient disposition
without modification.

[Illustration: FIG. 156.--INTERIOR OF A BASILICA AT POMPEII.
_Restored, from descriptions by various authors._]

Access is obtained to San Clemente through a forecourt to which the
name of the atrium is given. This is very much like the atrium of a
Roman house, being covered with a shed roof round all four sides and
open in the centre, and so resembling a cloister. The side next the
church was called the narthex or porch; and when an atrium did not
exist, a narthex at least was usually provided. The basilica has
always a central avenue, or nave, and sides or aisles, and was
generally entered from the narthex by three doors, one to each
division. The nave of San Clemente is lofty, and covered by a simple
wooden roof; it is s