The mother church is dedicated to the Saints Peter and Paul and it is the first parish in the town of Montese.
No trace remains of the original medieval building, as it was rebuilt from 1776 onwards in the late Baroque style.
Entrance is through a large portal, and the church has three naves, revealing a splendid and imposing Baroque altar and a marble balustrade (like the other altars, all made of polychrome marble) donated by the Chapter of Siena during the Napoleonic era.
The dome of the chancel is decorated with stucco high-reliefs depicting the four evangelists.
The side aisles house four paintings by Mattia Preti (which were purchased in Naples in the early nineteenth century and donated to the parish church by the Marquis Ferdinando Cattaneo):
- The Wedding at Cana,
- dinner at the Levis’,
- The Adoration of the Magi,
- The Nativity.
The other paintings are by Giovanni Donadio, of the Venetian school.
The church’s artistic décor includes a an organ dating from the late 18th century, from the Benedictine convent, and the choir screen, dating from the early 19th century, made of decorated and painted wood and bearing the town’s coat of arms.
There are also two finely carved, inlaid polychrome marble holy water fonts.
The baptistery and the font come from the Benedictine Abbey of St Michael the Archangel. The sacristy houses a small painting depicting the Virgin and Child, dating from the 15th century.
