Mentioned in historic sources starting from 914, Itri is thought to have obtained its name from iter (pathway, road) due to its position along the Via Appia.
According to other evidence this name is linked to veneration of the god Mitra, practiced in the area. In fact there was proof of the presence of a shrine to the god in S. Giacomo.
The town became part of the Duchy of Gaeta and later became a possession of the Fondi lords from l’Aquila. Near Itri in 1503 a battle took place during which Consalvo of Cordova conquered the French soldiers of the Duke of Nemours.
One of most famous local historic personalities is Michele Pezza (1771-1806), better known as „Fra Diavolo“, as he was called because of his exceptional wit and ability to escape his enemies, but also because of the courage and valour he showed in his fight against the French soldiers of General Championnet.
The medieval borgo is dominated by an impressive castle which looks over the town from the hill of Saint Angelo. The building, originally designed as a defensive stronghold has become the symbol of Itri.
At its highest part the fortress has one square and one polygonal tower; lower down a third cylindrical tower, also called the „Crocodile’s Tower“ is linked to the central part of the building by an impressive patrol way.
According to the legend linked to the tower, it was here that those sentenced to death were fed to a real crocodile.
The bell-tower of the collegiate church of Saint Maria Maggiore and the church of Saint Angelo can also be visited within the fine medieval town.