It returned under Perugia and Church control and then followed the fortunes of the Papal States till the Unification of Italy. Trevi was most prosperous in the early Middle Ages and during the Renaissance Period. SIGHTS TO SEE: the Church of St. Emiliano, Patron Saint of the town. The square and tower, the focal point of town life. The Mostaccio Arch , the original entry gate to the ancient fortress. The ancient Roman Walls are still perfectly preserved in via Fantosati and in via del Fiscale.