An authentic jewel of medieval art (which has been recognised as a National Monument) is located just outside the town centre. It was built on the remains of a 5th century temple dedicated to Diana, next to a Christian cemetery. The signs of Roman construction have vanished completely due to the numerous renovations in the various ages: the church was restored in the 9th and 10th centuries, and enlarged in the 11th and 12th centuries. This was mentioned by Pope Anastasius IV in a papal document of 1154 and its consecration, carried out by the Bishop of Rieti Gerard in November 1051, was then ratified by Federico I in December 1178.
The internal structure has three naves, in the upper part of the apse there is a fresco of the "Blessing Redeemer". The façade is gabled with an irregular roof and rough stone cladding. The portal is of great beauty thanks to the semi-circular arch supported by an architrave adorned with stylised leaves and animals, on the sides are two columns with foliage columns that are arranged in relation to the columns and half-pillars supporting the arch. In the bell tower, to the left of the façade, the alternation of single, double and triple lancet windows is clearly visible, the variety of materials present clearly confirms the various repairs carried out over time. The best preserved painting is the "Marriage of Santa Caterina d’Alessandria", dating from the first half of the 15th century.
At the right of the church is the architecturally interesting Baptistery of San Giovanni with a hexagonal plan, unique to the area and seemingly typical of northern Italy. Within, the interior is remarkable thanks to the frescoes on the walls, which belong to Umbrian-Latial-Abruzzese painters of the late 14th century. Stories of John the Baptist, Escape to Egypt and Massacre of the Innocents are depicted. The Last Judgement above the Baptistery door is particularly valuable. Other noteworthy pieces of artwork are the fresco of the Pieta and that of the figure of the Precursor. Restoration work was recently completed on the frescoes in the Church and Baptistery.