Three immense arches, which rank amongst the most remarkable remains in Rome, are all that are left of this once stupendous structure, which, until lately, was supposed to be the temple of Peace, erected by Vespasian at the close of the Judean war. But the great degeneracy of the workmanship, and its being wholly unlike all erections of that nature, has led to the opinion that the remains are neither of the time of Vespasian, nor those of the temple, which, with all the immense treasures it contained, was destroyed by fire, about one hundred years after its erection; but of a Basilica[186], erected by Maxentius on the ruins of the temple, and converted by Constantine into a Christian church. The stupendous proportions of this structure are shown by the three vaulted roofs, each seventy-five feet across, which rise above the surrounding buildings in huge but not ungainly masses. The vault of the middle arch, which is placed further back, forms part of a sphere; the side ones are cylindrical; all are ornamented with sunk panels of stucco-work. The church appears to have consisted of a nave and two aisles, divided by enormous pillars of marble, one of which now stands in front of the church of La Maria Maggiore. It is of a single block, of forty-eight feet in height, and sixteen and a half in circumference. Of the fine temple, di Venere e Roma,[187] the cella of each deity remains, with the niches, in which were their statues, and a portion of one of the side walls, which prove it to have been of vast size, great magnificence, and a chef-d’œuvre of architecture. The emperor Adrian himself drew the plans, which he submitted to Apollodorus, whose opinion respecting them is said to have been the cause of his untimely death. The temples, although they had each a separate entrance and cella, formed but one edifice; the substructure of which, having been recently excavated, is found to have been three hundred and thirty by one hundred and sixty feet. A noble flight of steps, discovered at the same time, between the arch of Titus and the church of St. Francesco, formed the approach of the Forum, which front, as well as that towards the Coliseum, was adorned with columns of Parian marble, six feet in diameter; and the whole was surrounded by a portico, with a double row of columns of grey granite. The walls and pavement of the interior were incrusted with fine marble, and the roof richly gilt. The Temple of Antoninus was erected by Marcus Aurelius in 178, in memory of Antoninus and his consort Faustina. The original portico, consisting of ten Corinthian columns of Cippolino marble, and a portion of the temple itself, now form the church of S. Lorenzo in Miranda.