The Colonna Santa.
At all events the surmise of the "Liber Pontificalis" shows how little credit is to be attached to the tradition that they once belonged to the Temple of Solomon at Jerusalem.[80] There are eleven left: of which eight ornament the balconies under the dome; two, the altar of S. Mauritius, and one (reproduced in our illustration) the Cappella della Pietà, the first on the right. It is called the colonna santa (the holy column), because it was formerly used for the exorcism of evil spirits. It was enclosed in a marble pluteus by Cardinal Orsini, in 1438.
The walls of the church were patched with fragments of tiles (tegolozza) and stone, except the apse and the arches, which were built of good bricks bearing the name of the emperor:—
Dominus Noster CONSTANTINVS AVGustus.
Grimaldi says that he could not find two capitals or two bases alike. He says also that the architraves and friezes differed from one intercolumniation to another, and that some of them were inscribed with the names and praises of Titus, Trajan, Gallienus, and others. On each side of the first gateway, at the foot of the steps, were two granite columns, with composite capitals, representing the bust of the emperor Hadrian framed in acanthus leaves.
The accompanying illustration, which was copied from an engraving of Ciampini, shows the aspect of the interior in the year 1588.
It gives a fairly good idea of the decorations of the nave, in their general outline; but fails to show the details of Constantine's patchwork. His system of structure may be better understood by referring to another of his creations, the basilica of S. Lorenzo fuori le Mura, of which a section of the interior is illustrated on [p. 135].
The atrium or quadri-portico was entered by three gateways, the middle one of which had doors of bronze inlaid with silver. The nielli represented castles, cities, and territories which were subject to the apostolic see. The doors were stolen in 1167, and carried to Viterbo as trophies of war.