Known from the 12th century, the church of San Martino was enlarged and renovated in the 16th century. The façade was built in 1613 and the bell tower completed in 1738.

The interior, in the counterfaçade, has an Immaculate Conception Protecting Siena during the Battle of Camullia by Giovanni di Lorenzo, commissioned by the city's commune in 1528. In the chapels are, among the others: the Circumcision of Jesus, one of Guido Reni's masterworks, the Martyrdom of St. Bartholomew (1637) by Guercino and the Nativity by Domenico Beccafumi.

The presbytery's restoration in the 17th century was patronized by the de' Vecchi family, who commissioned the decorations to the Mazzuoli family. Giuseppe Mazzuoli completed the statue of "St. Thomas of Villanova", and he helped his brother Giovanni complete the main altar.