Cosa

Cosa was a Latin colony founded in southwestern Tuscany in 273 BC, on land confiscated from the Etruscans, to solidify the control of the Romans and offer the Republic a protected port.

The Etruscan site may have been where modern Orbetello stands; a fortification wall in polygonal masonry at Orbetello's lagoon may be in phase with the walls of Cosa. The position of Cosa is distinct, rising some 113 metres above sea level and is sited 140 km northwest of Rome on the Tyrrhenian Sea coast, on a hill near the small town of Ansedonia. The town experienced a hard life and was never truly a prosperous Roman city, although it has assumed a position of prominence in Roman archaeology owing to the circumstances of its excavation.

Source: Wikipedia