The remains of the Roman town of Cosa, which was founded in 273 BC, can be seen just outside Ansedonia. Cosa was one of the many colonies founded by the Romans to control the territories they conquered. The town was developed according to a very precise urban plan – the blueprint of which they repeated many times throughout history.
Sacked and raised to the ground in 71 BC, Cosa was abandoned for almost 40 years until the Emperor Augustus decided to repopulate it and rebuilt the town giving it renewed prosperity for another 150 years. Subsequently, much of the population moved away and by the 5th century AD the ancient colony was a mass of ruins, devastated by the Visigoths of Alarico.
The acropolis maintains the ruins of the great ‘Capitolium’, a temple with three chambers from 2nd century BC. On a lower level is the area of the forum. On the north west side are traces of other buildings: the Basilica, the Comitium and a temple. The circuit of the polygonal walls measure 1,465 metres and large stretches are still visible today.