Castor, Aedes (Figs. 23, 63): the Temple of Castor (or of the Castors) at the southeast corner of the Forum Romanum flanked by the Vicus Tuscus and fountain of Juturna (Cicero Nat. D. 3.13; Plutarch Coriolan. 3.4; Dion. Hal. 6.13.4; Martial 1.70.3; also shown on the Marble Plan [FUR pl. 21.18; Rodriguez pl. 13]). According to tradition it was vowed at the battle of Lake Regillus in 493 B.C. by the dictator Postumius, first in the heat of battle and then after the Dioscuri were seen watering their horses at the spring of Juturna following the victory, and dedicated in 484 by the son of Postumius (Livy 2.20.12, Livy 2.42.5). The day of dedication is given as 27 January by everyone but Livy (Livy 2.42.5), who gives 15 July, the day of the Transvectio Equitum, which may be the date of the dedication of the first temple (Degrassi 403-4).

Its correct name was Aedes Castoris (Suetonius Caes. 10.1; Cass. Dio 37.8.2), and so it regularly appears, but we also find Aedes Castorum (e.g., Pliny HN 10.121; Not. Regio VIII; Chron. 146), and even Aedes Castoris et Pollucis (e.g., Asconius in Cic. Scaur. 46 [Stangl 28]; Suetonius Tib. 20).

The foundations of the oldest temple show a plan like that of Temple A at Pyrgi and suggest reconstruction with three rows of four columns preceding the cella and a cella flanked by lateral features. The Danish excavators believe there were three cellas, but lateral colonnades or alae seem more likely, and alae preferable.

The temple was rebuilt by L. Caecilius Metellus in 117 B.C. (Cicero Scaur. 46, with Asconius in Cic. Scaur. 46 [Stangl 28]; Cicero Verr. 2.1.154; Plutarch Pomp. 2.4). The concrete of the podium associated with this rebuilding is the earliest dated concrete known (Frank 78-79). Verres made some repairs to it (Cicero Verr. 2.1.129-54), and it was completely rebuilt by Tiberius and dedicated in A.D. 6 in his name and that of his brother Drusus (Suetonius Tib. 20; Cass. Dio 55.27.4; Ovid Fast. 1.707-8). Caligula in some way incorporated the temple in his palace, making an approach to the palace between the two statues, so the Dioscuri became his gatekeepers (Suetonius Calig. 22.2; Cass. Dio 59.28.5). Claudius abolished this modification. A restoration is ascribed to Domitian (Chron. 146), and here the temple is called Templum Castoris et Minervae, a name also found in the regionary catalogues. But scholars are agreed that the existing remains are essentially Augastan and that any subsequent restoration must have been limited. It is also one of the finest of all ancient Roman buildings.

It served frequently as a meeting place for the Roman senate (e.g., Cicero Verr. 2.1.129). Its stair was arranged to form a rostra with small stairs leading off from either end of a platform running the width of the temple at midstair (cf. Nash 1: figs. 239, 241). This must be one of the Rostra III of the regionary catalogues, although there is no indication that it was ever decorated with beaks. In the temple were kept the standards for weights and measures (cf. CIL 5.8119.4, 11.6726.2 = ILS 8638, CIL 13.10030.13-14), and a series of chambers in the podium in the intercolumniations closed by metal doors served as repositories for the imperial fiscus (CIL 6.8688-89) and for the wealth of private individuals (Juvenal 14.260-62).

As rebuilt in the Augustan period, the temple was octastyle, Corinthian, peripteral, with eleven columns on each long side and almost certainly a double row to either side of the relatively shallow pronaos. The podium is very high, the floor standing about 7 m above the Sacra Via. The pronaos is 9.90 m deep and 15.80 m wide, the cella is 19.70 m deep and 16 m wide, and the whole building is some 50 m long and 20 m wide. The podium is concrete, enclosing remains of earlier phases encased in tufa walls from which spur walls project to make the loculi for safekeeping of valuables. Under the columns, footings of travertine replace the tufa. From the pronaos a flight of eleven steps leads down to the rostra in front, 3.66 m above the street level. The rostra was provided with a railing and could accommodate a fairly large number of persons. From references in literature (Plutarch Sulla 33.4; Cicero Phil. 3.27), it is clear that there were similar arrangements in Metellus's temple. Of the superstructure, the three surviving columns on the east side were all that was standing in the fifteenth century, for the area near them was called Tre Colonne. These are of white marble, 12.50 m high, and carry an entablature with a plain frieze and a richly worked modillion cornice. The design of the capitals is especially admirable.

The temple was standing in the fourth century and was included in the regionary catalogues, but virtually nothing is known of its history in the imperial and medieval periods. Its identity was early lost, and in the early nineteenth century it was often wrongly identified, most frequently as the Temple of Iuppiter Stator.

Frank 78-79; MAAR 5 (1925): 79-102 (T. Frank); Lugli 1946, 179-83; Nash 1.210-13; ActaArch 56 (1985): 1-29 (I. Nielsen, J. Zahle, et al.), 59 (1988): 1-14 (I. Nielsen).