Lacus Curtius (Fig. 40): a monument in the Forum Romanum supposed to mark the place of a miraculous event of which three versions were given in the classical period: (1) A certain Procillus, possibly the tribunus plebis of 56 B.C., reported that in 362 B.C. a chasm opened here, which the soothsayers announced could only be closed by offering that quo plurimum populus Romanus posset. Thereupon a young patrician, M. Curtius, armed and mounted, rode his horse into the pit, which forthwith closed (Varro Ling. 5.148; Livy 7.6.1-6; Dion. Hal. 14.11.3-4; Val. Max. 5.6.2; Pliny HN 15.78; Cass. Dio fr. 30.1-2; Paulus ex Fest. 42L; Zonaras 7.25; Orosius 3.5). This was the commonest explanation. (2) Calpurnius Piso, the annalist and consul of 133 B.C., wrote that during the war between Romulus and Titus Tatius the Sabine leader Mettius Curtius, being hard-pressed by the Romans, rode his horse into a swamp in this place and so escaped (Varro Ling. 5.149; Livy 1.12.9-10; Livy 1.13.5; Dion. Hal. 2.42.5-6; Plutarch Rom. 18.4, who tells the story rather differently). This is the story commemorated by a relief found in 1553 between the Column of Phocas and the Temple of Castor and preserved in the Museo Capitolino Nuovo. It bears on its back an inscription of the praetor peregrinus L. Naevius Surdinus (CIL 6.1468 = 31662) of the early empire, but it is probably a copy of a late republican original. (3) An unidentified Cornelius and Q. Lutatius Catulus, the consul of 102 B.C., wrote that the lacus was a spot that had been struck by lightning in 445 B.C. and was then fenced off and marked with a puteal by the consul C. Curtius (Varro Ling. 5.150).

In the time of Augustus there was no sign of a lacus there (Ovid Fast. 6.403-4), but Suetonius (Suetonius Aug. 57.1) says that it was the custom for all Romans annually to throw a small coin in the lacus to discharge vows for the princeps' health and well-being. Thus it continued to have the associations with the underworld implicit in the first explanation of its origin, and there was an altar or altars there (Ovid Fast 6.403-4; Pliny HN 15.78).

The remains today consist of an irregular polygonal area, roughly 10.15 m x 8.95 m, which was enclosed in antiquity by a fence or balustrade of marble. Within this are parts of three layers of pavement, the lowest of slabs of cappellaccio, the middle of slabs of Monteverde tufa, and the topmost and poorest preserved of travertine. In the western part are cuttings for four rectangular bases, very likely Ovid's siccas . . . aras. The most conspicuous feature is a twelve-sided plinth of tufa, which had at its center a setting suitable for a puteal. One was often installed over a place struck by lightning and would make a convenient place for the Romans to deposit their coins.

Because there is no sign of any natural source of water in the vicinity nearer than the Cloaca, and all three explanations of the origin of the lacus plainly appear rationalizing inventions of one sort or another, we must conclude that it was a very ancient monument with strong associations with the cult of the dead, because, had it been simply a watering place, there would have been no hindrance to its removal.

J. Poucet, Recherches sur la legende Sabine des origines de Rome (Kinshasa, Zaire 1967); Nash 1.542-44; GV 104-16.