CIRCEII, a town of Latium, at the foot of Mons Circeius, and a short distance from the sea. It was originally colonized by the Romans in the reign of Tarquin the Proud, who deemed the position of the city favourable for commerce and for repressing the inroads of the Volsci. From its foundation till the date of the Latin War, B.C. 340, it seems to have been at one time subject to the Romans, at another to have espoused the cause of the Volsci, and sometimes to have been independent of either power. After the Latin War it was recolonized by the Romans; but it continued gradually to decline till the emperors Tiberius and Domitian, attracted to it by the pleasantness of its situation and the excellence of its oysters, erected villas in the neighbourhood. The ruins of the old city of Circeii are still distinctly visible on the Monte della Cittadella, about two miles from the sea.