Founded by the Romans, it was an important town along the Via Flaminius. At the fall of the Roman Empire, having already been Christianised by Bishop Emiliano, it was occupied by the Longobards and included in the Duchy of Spoleto. During the Middle Ages Trevi was ruled by Foligno and Spoleto. Political and military instability continued until the 16th century when, after domination by various lords (Trinci, Michelotti, Sforza), Trevi became part of the Papal States and remained under their domination, except for the brief Napoleonic period, until 1860.
Immersed in olive plantations, Trevi offers evidence of its Roman period in the mighty town walls (1st century BC) that encircle the historical centre; and the period of the Middle Ages can be seen in the three city gates: Porta del Bruscito, Porta del Cieco, Porta S. Fabiano, and the archway, Arco del Mostaccio. Leading from the walls that enclose the town is the Passeggiata, a magnificent avenue of 800 metres on level ground, that gives a striking panorama onto the valley below. Among the most interesting religious buildings are the church of Sant’Emiliano (12th century), with the altar of the Sacramento by Rocco da Vicenza (1522) and 16th-century frescoes attributed to Francesco Melanzio. Also worthy of a visit is the Gothic church of San Francesco from 1200; and in the 15th-century Palazzo Comunale, town hall, is the Pinacoteca art gallery with a Madonna by Pintoricchio and a Incoronazione di Maria by Lo Spagna. The church and the Pinacoteca, together with the Town Museum and the Archelogical Collection, make up the Raccolta d’Arte di S. Francesco, a collection set up in 1996 in a part of the ex-Convento di S. Francesco. The Raccolta includes the Museo della Civiltà dell’Ulivo that is the first public museum dedicated to olives and olive oil in Europe, which was created to give value to Trevi’s centuries-old tradition. Of interest are the richly decorated palaces such as the Collegio Etiopico Pontificio (16th century) frescoed by Federico Zuccari; Casa Petrucci (1500s); Palazzo Valenti (1500s); Palazzo della Prepositura Valenti (mid 1600s); and Renaissance Palazzo Lucarini, home to Trevi Flash Art Museum of contemporary art.