The Church of San Giovanni Evangelista was built in the 5th century by Empress Galla Placidia, who wished to release herself from a vow made during a sea storm, while voyaging from Constantinople to Ravenna to attend her son Valentinian’s installation on the throne of the West, after the death of her brother Honorius.

In the Middle Ages, a square portico rose before the entrance, now replaced by a wall delimiting a nice green area accessible through a beautiful 14th-century gothic gate. The bell tower dates back to the 10th century.

Divided into a nave and two side aisles, the church has undergone several changes over time. Furthermore, in 1944 it was severely damaged by an air attack that caused both the destruction of 12th-14th century frescos and of the apse mosaics. Fragments of the gorgeous floor mosaics of the basilica (1213), depicting scenes inspired by romances of the time, fantastic animals and protagonists of the fourth Crusade are now on display inside the building.