The decoration of the interior included the use of antique columns, which were sometimes adapted to their new place by cutting down or removing the bases. The walls above the nave arcading or entablature were adorned with mosaics, which also embellished the space above the Arch of Triumph and the semi-dome of the apse. The floors were covered with geometric patterns of marble sliced from columns and other antique fragments. The principal examples of basilican churches, still existing in =Rome=, are =St. Paul-without-the-walls=, =S. Clemente= and =S. Maria Maggiore=. The first named is of modern construction, completed in 1854, but preserves the plan and dimensions of the older church which was destroyed by fire in 1823. It had been begun in 380 by Theodosius, on a plan closely following that of the old St. Peter’s, except that the transepts of the bema project less and the atrium was abandoned, leaving only the narthex. Its construction and embellishment were continued by other emperors and by many popes, the munificence of the latter being commemorated in a series of portrait medallions of the popes which extends in a band above the arcade-arches on each side of the nave. The wall space above them is veneered with rare marbles, enclosing panels filled with paintings representing incidents in the life of St. Paul. Amid the somewhat extreme sumptuousness of the interior a feeling of the older character of a basilican church is preserved in the mosaics of the fifth century which adorn the arch of triumph, and in those of the apse which date from the early part of the thirteenth century. =S. Maria Maggiore= presents an original basilican plan of nave and single aisles, from each of which during the Renaissance was built out a square side chapel, surmounted by domes, giving the plan the form of a cross. But the interior of the nave dates from the time of Sixtus III in the fourth century and shows on each side a series of Ionic columns, supporting an entablature. Above this, as also over the arch of triumph, are mosaics of the fifth century. The =Church of S. Clemente= is notable for the retention of the atrium and also for the termination of the aisles in apses, a feature which suggests Byzantine influence. =Circular and Polygonal Plans.=--In addition to the basilican buildings of this period were some which involved a circular or polygonal plan, suggested probably by the circular temples and tombs of the Romans. They were applied in the early Christian era both to tombs, which in some cases were afterward converted into churches, and to baptistries. The latter were independent buildings, so called from their use at first solely for the sacrament of baptism. In later times, however, it became the custom to place the font inside the church; yet as late as the eleventh century was erected the famous =Baptistry of Florence=, in which even to this day every child born within the city is baptised.