The Church of San Francesco is situated on an older church built in 1268 and dedicated to the Virgin Mary. In the first half of the 14th century the Church was enlarged and during the 16th century it was restored. In 1777 the cotto tiles on the floor were remade. The architectural structure is very simple, in the style of the mendicant orders: the nave has wooden trusses, and the central pentagonal apse is flanked by two rectangular chapels. The church in Trevi is very similar to San francesco in Montefalco, dated back in the fourth decade of the 14th century. The apse has frescoes from the first half of the 14th century on the walls, depicting the stories of the life of the Virgin Mary. At the center of the apse there is a cross of the beginning of 1300. The walls retain traces of frescoes and large altars as requested by the Catholic Reformation rules. Worth noting: the canvas with the Madonna and Child and the Souls in Purgatory by Ascensidonio Spacca, known as il Fantino, and the monumental organ, considered "a rare surviving specimen of this type that was defined, during the Renaissance, as a wall-organ". It was built by the master Paolo Pietro di Paolo di Montefalco in 1509, and was played for the first time at Christmas Day. The restoration of the ancient instrument, carried out by Organi Pinchi Foligno, began in the 1990's, with original 16th-century materials. Opened in 2005, it is one of the oldest organs remaining in Europe dating back to the sixteenth century.