Founded by the Romans, it was an important town along the Via Flaminius. 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.
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 Archaelogical 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.
In the vicinity worthy of a visit is the church of the Madonna delle Lacrime, which was erected in 1487 to commemorate a miracle and that has a fresco by Perugino. In the hamlet of Bovara is the oldest olive tree in Umbria, 9 metres high and reckoned as 1700 years old. It is known as the tree of Sant’Emiliano because according to tradition in 304, the future patron saint of the town, was tied to it and martyred. Of particular environmental interest is the course of the Clitunno river, known for its clear fresh waters, through the exceptional landscape of the Southern Umbrian (or Spoleto) Valley.