Agrippa was consul for the third time in B.C. 27, so that the building is now 1906 years old. Another inscription in smaller characters stands under this upon the two upper ledges of the architrave, commemorating the restoration of the building by Severus and Caracalla. The pediment, as may be seen by the holes of the metal fastenings, formerly contained a bronze relief representing Jupiter hurling thunderbolts upon the giants. The roof of the pronaos was originally arched, but the vaulting has been replaced by strong beams, and on the outside the gilded bronze has been replaced by lead. In the interior of the pronaos, on each side of the entrance are two huge niches which formerly contained the statues of Augustus and Agrippa, but are now empty. The pronaos is connected with the rotunda by two massive projections of masonry ornamented at the sides with marble pilasters and exquisitely worked reliefs in pentelic marble representing candelabra and sacrificial implements entwined with wreaths. These connecting walls originally rose to an equal height with the walls of the rotunda, but are now hidden by the bell towers, erected by Bernini in the time of Urban VIII. about A.D. 1625. The doorway is of magnificently carved marble slabs, and the folding doors, moving on massive hinges fixed in two projecting pilasters, are of exquisitely worked bronze. The rotunda rests on a rectangular base, similar to those which support the cylindrical part of the mausoleum of Hadrian and the tomb of Cecilia Metella. In the parts where the thickness of the wall is not lessened by niches in the interior, it has the amazing breadth of nineteen feet of solid brickwork. In addition to this it is strengthened with numerous arches built into the wall. Three cornices run round the exterior of the rotunda and divide it into three rings, the lowest of which was faced with marble, and the two upper with stucco. The dome springs from the second cornice, and consists first of a ring of masonry seven feet high, and then of six concentric rings, presenting on the exterior the appearance of six steps. The top is flat, and is pierced in the centre with a large round opening twenty-seven feet in diameter. Round the opening is a ring of ornamental gilded bronze, which is the only part of the old bronze gilt roof now remaining. The masonry of the dome is of wedge-shaped pumice stones, chosen for this purpose on account of their lightness. The same kind of stone is used in several other buildings in Rome where lightness combined with moderate strength is required. The exterior of the dome is flat and heavy, and impressive only from its stern and massive solidity. The proportions of the interior are altogether different, and have been universally admired for their elegance, and the exquisitely simple taste with which they are decorated. The lower part contains eight deep niches, alternately semicircular and square, in one of which the entrance doors