Remains of the Temple of Augustus, from a sketch by Ligorio.

The construction of a temple in honor of the deified founder of the empire was begun by his widow Livia, and Tiberius, his adopted son, and completed by Caligula. An inscription discovered in 1726, in the Columbaria of Livia on the Appian Way, mentions a C. Julius Bathyllus, sacristan or keeper of the temple. Pliny (xii. 19, 42) describes, among the curiosities of the place, a root of a cinnamon-tree, of extraordinary size, placed by Livia on a golden tray. The relic was destroyed by fire in the reign of Titus. Domitian must have restored the building, because the rear wall of the temple, the murus post templum divi Augusti ad Minervam, is mentioned in contemporary documents as the place on which state notices were posted. It has been excavated but once, in June, 1549, when the Forum, the Sacra Via and the Street of the Tuscans were ransacked to supply marbles and lime for the building of S. Peter's. Two documents show the wonderful state of preservation in which the temple was found. One is a sketch, taken in 1549, by Pirro Ligorio, which, through the kindness of Professor T. H. Middleton,[56] I reproduce from the original, in the Bodleian Library; the other is a description of the discovery by Panvinius.[57] The place was in such good condition that even the statue and altar of Vortumnus, described by Livy, Asconius, Varro and others, were found lying at the foot of the steps of the temple.

The Sacellum Sanci, or Shrine of Sancus on the Quirinal.[58] The worship of Semo Sancus Sanctus Dius Fidius was imported into Rome at a very early period, by the Sabines who first colonized the Quirinal Hill. He was considered the Genius of heavenly light, the son of Jupiter Diespiter or Lucetius, the avenger of dishonesty, the upholder of truth and good faith, whose mission upon earth was to secure the sanctity of agreements, of matrimony, and hospitality. Hence his various names and his identification with the Roman Hercules, who was likewise invoked as a guardian of the sanctity of oaths (me-Hercle, me-Dius Fidius). There were two shrines of Semo Sancus in ancient Rome, one built by the Sabines on the Quirinal, near the modern church of S. Silvestro, from which the Porta Sanqualis of the Servian walls was named, the other built by the Romans on the Island of the Tiber (S. Bartolomeo) near the Temple of Jupiter Jurarius. Justin, the apologist and martyr, laboring under the delusion that Semo Sancus and Simon the Magician were the same, describes the altar on the island of S. Bartolomeo as sacred to the latter.[59] He must have glanced hurriedly at the first three names of the Sabine god,—SEMONI SANCO DEO,—and translated them ΣΙΜΩΝΙ ΔΕΩ ΣΑΓΚΤΩ. The altar on which these names were written, the very one seen and described by S. Justin, was discovered on the same island, in July, 1574, during the pontificate of Gregory XIII. The altar is preserved in the Galleria Lapidaria of the Vatican Museum, in the first compartment (Dii).

Statue of Semo Sancus.

The shrine on the Quirinal is minutely described by classical writers. It was hypæthral, that is, without a roof, so that the sky could be seen by the worshippers of the "Genius of heavenly light." The oath me-Dius Fidius could not be taken except in the open air. The chapel contained relics of the kingly period, the wool, distaff, spindle, and slippers of Tanaquil, and brass clypea or medallions, made of money confiscated from Vitruvius Vaccus.

Its foundations were discovered in March, 1881, under what was formerly the convent of S. Silvestro al Quirinale, now the headquarters of the Royal Engineers. The monument is a parallelogram in shape, thirty-five feet long by nineteen feet wide, with walls of travertine, and decorations of white marble; and it is surrounded by votive altars and pedestals of statues. I am not sure whether the remarkable work of art which I shall describe presently was found in this very place, but it is a strange coincidence that, during the progress of the excavations at S. Silvestro, a statue of Semo Sancus and a pedestal inscribed with his name should have appeared in the antiquarian market of the city.