422. Baptistery of Constantine. (From Isabelle.) Scale 100 ft. to 1 in.
When from these we turn to the Tomb or Baptistery of Constantine, built some time afterwards (Woodcut No. [422]), we find the roof supported by a screen of eight columns, two storeys in height, and through all its alterations can detect the effort to make the interior ornamental. It has, however, a portico, but this again is practically an interior, both ends being closed with apsidal terminations, so that it really forms a second apartment, rather than a portico. In both these respects it is in advance of the building next to it in age that we know of—the Octagon at Spalato—which it otherwise very much resembles. The eight internal pillars instead of being mere ornaments have become essential parts of the construction, and the external peristyle has disappeared, leaving only the fragment of a porch.
423. Plan of the Tomb of Sta. Costanza, Rome. (From Isabelle, ‘Édifices Circulaires.’) Scale 100 ft. to 1 in.
The tomb which the same Emperor erected to contain the remains of his daughter Constantia, is another example of the same transitional style. The interior in this instance is vaulted, but so timidly that twenty-four pillars are employed to sustain a weight for which half that number would have been amply sufficient. In the square niche opposite the entrance stood the sarcophagus of the princess, now in the Vatican. The roof of the aisle is adorned with paintings of the vintage and scenes of rural life, which, like all those on the tombs of Pagan Rome, have no reference to the sepulchral uses to which the building was dedicated. The whole internal diameter of the tomb is 73 ft., that of the dome 35.
In front of the building is a small crypto-porticus similar in arrangement to that of her father’s tomb, and beyond this is an oblong space with circular ends, and surrounded on all sides by arcades; its dimensions were 535 ft. by 130, and, though so ruined as hardly to allow of its arrangements being restored, it is interesting as being perhaps the only instance of the “forum,” which it is probable was left before all tombs in those times, and traces of which may perhaps be found elsewhere, though as yet they have not been looked for.
424. Plan of San Stefano Rotondo. (From Gutensohn and Knapp.) Scale 100 ft. to 1 in.
The only other important circular building within the walls of Rome of this early age is that known as S. Stefano Rotondo. Though there is nothing to fix its date with any precision, it is almost certain that it belongs to the fifth century of the Christian era.[[289]] It is 210 ft. in diameter, and its roof was supported by two ranges of columns, circularly disposed in its interior; and on the first or inner range rested a horizontal architrave like that of St. Peter’s. In the outer one the pillars support arches like those of St. Paul’s.[[290]] All the pillars are taken from older buildings. The outer aisle was divided into eight compartments; but in what manner, and for what purpose, it is not now easy to ascertain, owing to the ruined state of the building, and to its having been so much and so frequently altered since it was first erected. Nor can it be determined exactly how it was roofed; though it is probable that its arrangements were identical with those of the great five-aisled basilicas, which it closely resembles, except in its circular shape.
