Identification: Forum Augustum/Augusti In the 16th century, this fragment was still in one piece with the now missing fr. 16c. A drawing by G. P. Bellori of the missing piece allowed G. Carettoni to interpret the line at the bottom of this fragment as the lateral wall and colonnade of a pronaos of a podium temple with a frontal staircase and a central altar. Joining fr. 16d to these further allowed Carettoni to make certain observations about the temple and the surrounding portico and finally to identify the portico as the SE portico in the Forum of Augustus, and the line below as the SE podium wall of the Temple to Mars Ultor (PM 1960, p. 74). More of the building is visible in fr. 16a. Also called forum Martis, the Forum of Augustus was second in the row of great imperial fora in Rome. The structure, which contained the great Temple of Mars Ultor, was dedicated by Augustus and his grandsons Gaius and Lucius in 2 BCE, when the temple was still unfinished (LTUR II, p. 289). It was located just northeast of the Roman forum, next to a stretch of the Argiletum, perpendicular to the forum Iulium, whose E side it abutted or was separated from by a street (Richardson 1992, pp. 160-61). A 30 meter tall fire wall encased it on the northeast (LTUR II, p. 290). Considered by Pliny one of the three most beautiful structures in Rome, Augustus' forum consisted of a large, rectangular space (ca. 125 x 90 m), paved with marble slabs and flanked on both sides by porticoes that were raised three steps above the level of the central courtyard. Above these lateral colonnades ran a deep attic, richly decorated with shields and copies of the caryatids in the Erectheum in Athens. The back walls of the porticoes were articulated with niches and engaged columns, and at the NE end, they opened up into the two great hemicycles on either side of the temple. The row of engaged columns in the back walls continued in front of these hemicycles as columns on plinths (Richardson 1992, p. 161). Two superimposed rows of niches - with larger niches in the center - adorned the walls of these semi-circular exedrae; inscriptions found in situ and a passage from Ovid (fast. 5.563-566) suggest that the niches contained on one side statues of Aeneas surrounded by members of the Iulio-Claudian family and possibly the kings of Alba Longa, on the other side Romulus, flanked by great men from Rome's past (LTUR II, pp. 290-91). One of these niches may be visible as a recessed square in fr. 16a. At the end of the SE portico, a small opening on the right gave access to a staircase that led to the Porticus Absidata; at the end of the opposite portico lay a square hall that held a colossal statue, believed by some scholars to have represented Augustus (LTUR II, p. 292). On either side of the temple, between the temple and the lateral porticoes, two arches (built by Tiberius in honor of Germanicus and Drusus around 18 CE) led to two staircases. The SE arch, known today as the Arco dei Pantani, gave access to a small, triangular space above a set of stairs; the NW arch, possibly the one dedicated to Drusus, led to two sets of stairs and to a street behind the forum through which one entered the Subura neighborhood (LTUR II, p. 292, fig. 117; Richardson 1992, p. 161). The architectural details of the SW end of the forum, and thus the main approach from the forum Iulium, are not known, as it has never been excavated. Small openings in the back walls of the lateral porticoes gave access to the Forum Transitorium and later to the Forum of Trajan.

The Temple to Mars Ultor dominated the far (NE) end of the forum, where it backed onto the tall fire wall (LTUR II, fig. 117). It was octastyle, peripteral sine postico, and situated on a tall platform accessed by a frontal staircase. Platforms flanked the stairs on either side, and an altar sat in the center towards the front. The columns surrounding the cella stood on plinths. Inside the cella, lateral platforms supported six columns on plinths and matching endorsed columns on each side of the wide, vaulted nave. In the rear, an apse was approached by five stairs; here, a wide statue base held the cult statue of Mars Ultor (LTUR II, pp. 291-92). The statue of Mars was possibly flanked by statues of Venus and the deified Iulius Caesar (Richardson 1992, p. 163; against this, see V. Kockel in LTUR II, p. 292). Augustus' forum served a variety of purposes. Notable among these was its function as a gallery for great works of art, including a quadriga and two pictures by Apelles, and its role as Rome's foreign office (Richardson 1992, p. 162).

Significance Thanks to a Renaissance depiction of this fragment when still in one piece with the now missing fr. 16c, Carettoni was able to identify it as belonging to the Forum of Augustus and the Temple of Mars Ultor.

Text by Tina Najbjerg