Stagnum Agrippae

A large artificial basin filled with still water created by M. Agrippa in a natural, marshy depression (the palus Caprae) just W of his *Thermae in the central *Campus Martius (Buzzetti; for the name, e.g., Tac., Ann. 15.37: in stagno Agrippae). Oriented on a N–S axis in accordance with the neighboring Agrippan buildings and the *Theatrum Pompeium, the Stagnum has fairly well-determined boundaries: the *Pantheum, *Basilica Neptuni, and Thermae form its E limit (corresponding to modern Via di Torre Argentina), while remains excavated below Corso del Rinascimento mark its W bank (Ghini, Colini 1938). A flight of three marble steps and a portion of a peperino wall unearthed in Piazza di S. Eustachio, equidistant from the Stagnum’s E and W boundaries indicate the N edge (Ghini figs. 1, 18). The stairs and wall are of Augustan date and formed an access point to the Stagnum; the basin was enclosed by a low wall which rose at least 1.5 m above the water level on the N side (the extant wall is composed of one course, H. c. 0.66 m, with cramp cuttings on its top surface indicating another course atop it, and the elevation of the topmost step indicates the highest possible water level). The S edge of the Stagnum is depicted on the Severan Marble Plan with a single line, probably representing a similar enclosure wall, just N of and parallel to the *Hecatostylum (Rodríguez Almeida, Forma pls. 31-32, frag. 39a). These data suggest a basin of considerable size (c. 240 x 190 m). Most believe the Stagnum received its water from the *Aqua Virgo and drained into the *Euripus (Coarelli 827-28, Buzzetti, Richardson; contra, Lloyd 196, who believes it may have been fed by run-off from the baths). If fed by the Virgo, the water would have been quite clear and cool, so perhaps the Stagnum functioned as a natatio (swimming pool) for the Thermae of Agrippa (Coarelli 828, Lloyd 195, Buzzetti). The lake was also broad and deep enough to be navigable; Tacitus describes a lavish banquet held aboard a pleasure barge which was steered about the Stagnum by tugs (Ann. 15.37). Apparently, there was also sufficient room on the Stagnum quays (crepidines) for brothels and parading harlots (Tac., loc. cit.). Further, as darkness fell, the adjacent *Nemus of Agrippa was filled with song and twinkling lights (Tac., loc. cit.); by the mid-1st c. A.D. the surrounding area had become a residential neighborhood (Tac., loc. cit.: iuxta nemoris et circumiecta tecta; cf. Colini 1941 for pre-Domitianic foundations E of the Stagnum).