San Gimignano rises on a hill (334m high) dominating the Elsa Valley with its towers. Once the seat of a small Etruscan village of the Hellenistic period (200-300 BC) it began its life as a town in the 10th century taking its name from the Holy Bishop of Modena, St. Gimignano, who is said to have saved the village from the barbarian hordes. The town increased in wealth and developed greatly during the Middle Ages thanks to the "Via Francigena" the trading and pilgrim's route that crossed it. Such prosperity lead to the flourishing of works of art to adorn the churches and monasteries.
http://www.sangimignano.com/sstoriai.htm