A vast number of fragments of columns, of inscriptions, and of architectural ornaments have been dug up at various times on the site of Trajan’s Forum. The great granite columns which now lie near the base of the pillar were found in laying the foundations of the Church of S. Maria in Loreto, by the architect, the elder San Gallo, and are mentioned as lying near that church in the middle of the sixteenth century. The equestrian statue of Marcus Aurelius, in the Piazza del Campidoglio, stands upon a pedestal made by Michael Angelo out of an immense fragment of entablature found on the site of Trajan’s Forum.
An inscription, which is now built into the wall on the north of the pillar, commemorates the remission of all debts to the emperor’s private purse (fiscus) by Hadrian, a fact which we find also mentioned in Dion Cassius and Spartianus. The latter writer adds that it was in the Forum of Trajan that Hadrian publicly burnt the list of his debtors, and the inscription was no doubt intended to mark the spot of this act of liberality or bribery.
Ruins of the Forum Julium.
The ruins of two portions only of the Forum Julium, which adjoined that of Trajan, have been discovered in modern times. The first is a considerable part of the outer wall of the Forum, standing in the court of the house No. 18 in the Via del Ghetarello, a small street which opens out of the Via di Marforio, near the Carcer and the Church of SS. Martina e Luca. This ruined wall consists of three arches composed of large blocks of peperino and travertine skilfully cut and joined without mortar and under-built by another arch, as if in order to enable the wall to bear a great weight. The length of the fragment of wall is about 50 feet and the highest point about 30 feet.
The other relic of Cæsar’s Forum is now no longer visible. We obtain our information about it from Palladio, the architect, about the middle of the sixteenth century, who relates that while he was at Rome the ground-plan of a temple was uncovered in digging the foundations of a house between the Salita di Marforio and the temple of Mars Ultor, a description which points plainly to the block of houses behind SS. Martina e Luca. There was a peculiarity in the inter-columniations of this temple, which Palladio particularly remarked. The distance between the columns, he says, was the eleventh part of the diameter of a column less than a diameter and a half.
Forum of Augustus.
Temple of Mars Ultor.
The almost universal opinion of Roman topographers now is that the three Corinthian columns on the left-hand side of the Via Bonella and the massive arch which leads from it into the Via di Tor di Conti are the remains of the Temple of Mars Ultor, which Augustus built in his Forum, and of the north-eastern portion of the enclosing wall.
This opinion was already held by Palladio in the sixteenth century, but the Italian antiquaries since his time have adopted the most various hypotheses on the subject. There is, it is true, no actual proof that this was the temple of Mars Ultor, but there is strong presumptive evidence that it was so. The ‘Catalogue of the Curiosum’ places it next to the Forum Julium in the eighth region. Now the eighth region was bounded on the east, in this neighbourhood, by the Quirinal Hill and the Via del Sole, or a street a little to the east of it, and we are tolerably sure that the forum transitorium filled up a great part of the space between the temple in question and the above-mentioned street, and that the Forum Julium intervened between it and the Forum Romanum, while the Forum Trajani limits the space to the westward within which we can suppose the Forum Augusti to have been. Thus the only space left in the eighth region within which the Forum of Augustus can be supposed to have been contained, is that bounded by the Via della Croce Bianca, the Via del Priorato, and the Via di Tor di Conti.
The ruins of the temple consist of three lofty fluted Corinthian columns, a pilaster of white Carrara marble, a part of the surmounting architrave, and the corresponding wall of the cella of the temple. Antiquarians are of opinion that the purity of style and elegance of these columns, and their ornamentation, forms a strong proof that they were designed and executed in the best times of Roman architectural art, and cannot belong to a period later than that of Augustus. The richest decorative work is to be seen under the roof of the portico, between the columns and the wall of the cella.
Exterior wall. Arco dei Pantani.