Eth. CASTRUM INUI
an ancient city of Latium, the foundation of which is ascribed by Virgil to the Alban kings. (Aen.
6.772.) No mention of it is found in any historical or geographical writer, and Pliny does not even include it in his list of the extinct cities of Latium; but it is repeatedly alluded to by the Roman poets. Silius Italicus assigns it to the Rutuli, and Ovid places it on the coast between Antium and Lavinium. (Sil. Ital. 8.361
; Ovid, Ov. Met. 15.727
.) Both these writers call it Castrum simply, Virgil being the only author who has preserved its fill name.
It is clear that the town had ceased to exist at a very early period, which may account for the error of Servius (ad Aen. l.c.
) and Rutilius (Itin.
1.232), who have confounded it with Castrum Novum on the coast of Etruria.
But it left its name to the adjoining district, which is mentioned by Martial under the name of the “Castrana rura,” as a tract noted, like the adjacent Ardea, for its insalubrity. (Mart. 4.60. 1
: where, however some editions read Paestana.)
The passage of Ovid is the only clue to its position. Nibby supposes it to have occupied a height on the left bank of the little river called Fosso dell' Incastro,
which flows by Ardea, immediately above its mouth; a plausible conjecture, which is all that can be looked for in such a case. (Nibby, Dintorni,
vol. i. p. 440.)