Round Temple of Hercules in the Forum Boarium.
The Ara Maxima Herculis. This altar, the oldest in Rome, was raised in memory of the visit of Hercules to our country. Tacitus and Pliny attribute its construction to Evander the Arcadian, forgetting that in prehistoric times the tract of land on which the altar stood, between the Forum Boarium and the Circus Maximus, was submerged by the waters of the Velabrum. It was at all events a very ancient structure, held in great veneration. Its rough shape and appearance were never changed, as shown by a precious—yet unpublished—sketch by Baldassarre Peruzzi which I found among his autographs in Florence. A round temple was built near the altar, in later times, of which we know two particulars: first, that it had a mysterious power of repulsion for dogs and flies;[41] second, that it contained, among other works of art, a picture by the poet Pacuvius, next in antiquity and value to the one painted by Fabius Pictor, in the Temple of Health, in 303 b. c.[42] The Temple of Hercules, the Ara Maxima, and the bronze statue of the hero-god were discovered, in a good state of preservation, during the pontificate of Sixtus IV., between the apse of S. Maria in Cosmedin (the Temple of Ceres), and the Circus Maximus. We have a description of the discovery by Pomponio Leto, Albertini, and Fra Giocondo da Verona; and excellent drawings by Baldassarre Peruzzi.[43]
Except the bronze statue, and a few votive inscriptions, which were removed to the Capitoline Museum, everything—temple, altar, and platform—was levelled to the ground by the illustrious Vandals of the Renaissance.
The Roma Quadrata. According to the ancient ritual, the founder of a city, after tracing the sulcus primigenius or furrow which marked its limits, buried the plough, the instruments of sacrifice, and other votive offerings, in a round hole, excavated in the centre of the marked space. The round hole was called mundus, and its location was indicated by a heap of stones, which in course of time took the shape of a square altar. The mundus of ancient Rome was located in the very heart of the Palatine, in front of the Temple of Apollo, and the altar upon it was named the Roma Quadrata. This name has been much discussed, and it has even been applied to the Palatine city itself, although it is an established fact that there is, strictly speaking, no connection between the two. The controversy has been resumed lately by Professor Luigi Pigorini in a paper still unpublished which was read at the sitting of the German Institute, December 17, 1890; and by Professor Otto Richter in his pamphlet Die älteste Wohnstätte des römischen Volks, Berlin, 1891.
In view of the ignorance of ancient writers on this subject, and the almost absurd definitions they give of the word, we had come to the conclusion that the altar had been removed or concealed by Augustus, when he built the Temple of Apollo and the Portico of the Danaids, in 28 b. c. A remarkable inscription discovered September 20, 1890 (to which I shall refer at length later), by mentioning the Roma Quadrata as existing a. d. 204, shows that our opinion was wrong, and that the old altar, the most venerable monument of Roman history, had survived the vicissitudes of time, and the transformation of the Palatine from the cradle of the city into the palace of the Cæsars.
In December, 1869, when the nuns of the Visitation were laying the foundations of a new wing of their convent on the area of the Temple of Apollo,[44] I saw a line of square pilasters at the depth of forty-one feet below the pavement of the Portico of the Danaids, and in the centre of the line a heap of stones, either of tufa or peperino, roughly squared. It is more than probable that, in 1869, I did not think of the Roma Quadrata, and of its connection with those remains, so deeply buried in the heart of the hill; but I am sure that a careful investigation of that sacred spot would lead to very important results.
Ara of Aius Locutius on the Palatine.