In the vicinity of Caso on the old mule-track to Gavelli, this small, elegant, Romanesque building is a typical example of perfect, square-cut, brick stonework.

The church of Santa Caterina has an arched portal, a single-lancet window and bell gable and the roof truss covers the completely frescoed single-nave interior and apse. A stone seat runs along the side walls.

The richly decorated frescoes have various points of interest, including the lively folklore featured in the depiction of the Judgement (14th century frescoes), the pictorial tale of the Stories of Saint Cristina (14th and 15th century frescoes) and works by artists working mainly in Umbria in the 15th and 16th centuries, such as the Maestro of Eggi (two figures of St. Cristina, Madonna with Child and the Saints James and John, left-hand wall) and Spagna (St. Cristina of 1524, left-hand wall).