Curia Iulia: the curia begun by Julius Caesar in 44 B.C. to replace the Curia Hostilia as rebuilt by Faustus Sulla (Cass. Dio 44.5.2, Cass. Dio 45.17.8) and completed by Augustus in 29 (Augustus RG 19; Cass. Dio 51.22.1). As completed, it was preceded by a Chalcidicum; this is shown on coins (B. M. Coins, Rom. Rep. 2.16 nos. 4358-59; B. M. Coins, Rom. Emp. 1.103 nos. 631-32) as a porch with wide-spaced Ionic columns raised on a high podium. It extends beyond the façade of the curia to either side, and, because there is no stair in front, it must be presumed that stairs or ramps led up to it from behind. A very light architrave joins the columns, and if there was a roof, it does not appear. On the coins the gable of the roof of the curia is shown surmounted by large acroteria; a Victoria is mounted on a globe at the peak, and warrior figures are at the corners. In the pediment is a single figure of uncertain character. In the interior of the curia Augustus put a statue of Victoria from Tarentum (Cass. Dio 51.22.1) and two paintings, an encaustic Nemea by Nicias and a double portrait by Philocares (Pliny HN 35.27-28).

This curia was in Comitio (Pliny HN 35.27) and probably had the same orientation as the curia of Diocletian, aligned with the tabernae of the Forum Iulium, but it may have stood somewhat to the northwest of Diocletian's to allow a place for the Chalcidicum's lateral colonnade and the Ianus Geminus (but see Morselli and Tortorici, 22-27). Domitian rebuilt the curia, evidently in connection with his work on the Forum Transitorium (Hieron. a. Abr. 2106). Because at that time he built a new Ianus Quadrifrons (see Ianus Quadrifrons [2]), it is probable that he destroyed the Ianus Geminus and relocated the curia in its present position. At the same time he must have eliminated or redesigned the Chalcidicum. The curia burned down in the fire of Carinus of A.D. 283, and Diocletian restored it (Chron. 148). It is Diocletian's building that we see today (Fig. 39).

It is a large plain hall of brick-faced concrete, a broad rectangle 25.20 m deep and 17.61 m wide with a very lofty roof, which necessitated the addition of a great rectangular buttress at each corner. It was approached by a stair that ran across most of the façade, returning to the façade at the ends. The lower part of the façade was veneered with plates of marble, and the parts above were finished with stucco. There is a single axial door, above which are three large rectangular windows with slightly bowed lintels. The low pediment is framed by travertine consoles supporting a brick cornice. There is a single window high in each side wall of the building and another in back, where there are also doors to either side leading to the main hall, the precise function of which is unknown.

The interior has been restored according to the evidence found in the dismantling of the church of S. Adriano, into which it had been converted. To either side are three broad low steps to accommodate the curule chairs of the more important senators, the top one broader than the others for those who stood. At the far end, between the doors mentioned above, is a low dais of two steps for the presiding magistrate. The central floor is paved with panels of opus sectile, in which porphyry and serpentine figure large. Along each side wall is a marble wainscoting finished with a molding, above which are three widely spaced niches, the center one with an arched head, the others flat-headed. These seem to have had rich architectural frames. Nothing remains of the decoration of the upper walls.

The curia was converted to use as the church of S. Adriano under Pope Honorius I (A.D. 625-638). The bronze doors were removed in the seventeenth century by Borromini, restored and relocated to serve the baptistery of S. Giovanni in Laterano. At that time several coins were found between the plates, including one of Domitian. In 1935-1938 the church was deconsecrated, and the curia was restored to its ancient form. It is now used for the mounting of archaeological exhibitions of a temporary nature.

To the northwest of the curia other buildings were added between the time of Augustus and the rebuilding of Diocletian. The plan of these is shown in a drawing by Antonio da Sangallo il Giovane (Lugli 1946, 133 fig. 27). These buildings seem not to have been in close sequence with the curia, but aligned with it. They are commonly identified as the Secretarium Senatus and Atrium Minervae and ascribed to Domitian. Nash proved this identification mistaken. That to the northwest, of which remains were built into the northeast and southeast walls of the church of SS. Luca e Martina, is in all probability the Athenaeum of Hadrian (Aur. Vict. Caes. 14.3), known also as the Atrium Minervae, an auditorium for rhetorical and poetical performances. Sangallo's drawing shows that next to it was a long narrow hall with a row of pillars down the middle, the walls broken into a series of rectangular bays, which might well have held cupboards in which to keep books. This then would be the library known to have been attached to the Athenaeum (Sid. Apoll. Epist. 2.9.4). The area between this and the curia was probably an open court. A. Bartoli, Curia senatus (Rome 1963); Nash 1.301-3; RömMitt 85 (1978): 359-69 (L. Richardson); C. Morselli and E. Tortorici, Curia, Forum Iulium, Forum Transitorium (Rome 1989), especially 1-263.