The apse is decorated externally with hanging archlets supported by pro-thrones, columns and semi columns. The exterior masonry is an example of a well-kept Romanesque stonework. However, the most peculiar feature of this building is the “rose window design” incised in the brickwork of the right internal wall, near the entrance. The right chapel hosts frescoes of Evangelists (in the vault), Christ at Calvary (in the lunette), Christ in the garden and St. Michael (sub-arch), of the 16th century. The apse presents a Nativity of the 16th century and a Mystical Marriage of St. Catherine, dated 1519;  above on the sides there is a fresco  of the early 14th century depicting Angels. On the left transept there is a fresco of the Madonna and Saint of the 16th century. Up on the left wall there is a detached fresco of the 15th century representing a Crucifix and Saints, a Saint and St. Augustine of the 15th century; and Our Lady of the Rosary of the 17th century. The remains of the artistic heritage of this parish church (once rich and important) are two wooden Madonnas of the 14th century, a canvas of a Deposition (derived from Daniele da Volterra) and the surviving parts of the fresco decoration (in a poor state of conservation). A big Roman monolithic cup made of basalt is used as baptismal font. A Madonna enthroned with Angels and Saints, a wide fragment of an antependium is an artwork made by an unidentified Umbrian in the early 14th century known as the Master of Cesi (preserved in the Diocesan collection of Spoleto).