The area of Agosta was inhabited since prehistoric times. It is mentioned in Augustus's Res Gestae as the source of the Aqua Marcia aqueduct, and after that it took its name from the Roman emperor. In 1051 AD a castle is mentioned here, which later was a possession of the monastery of Subiaco.
Main sights
Medieval castle
Arch of the Cardinal o della Porta, built in 1503 near a bridge which at the time crossed the Aniene river.