Overlooking the lush green Sorbo Valley, where the ancient city of Veio once stood, Formello has even earlier origins, but it was during the Etruscan period that it became an important economic and cultural centre, as is clearly indicated by archaeological finds, in particular the large tombs with their grave goods.
The Etruscans created a complex system of underground pipelines in the area to convey river water. Hence the present name of the town, which derives from 'forma' - in Latin canal.
It was however in the Middle Ages that, in order to cope with Saracen raids, the population established fortified settlements in the area, including old Formello.
The town then underwent successive phases of development with the Orsini (13th-17th centuries) and Chigi (17th century-1952) families, and the old-town centre has never since lost it age-old charm.