San Martino is a Roman Catholic church located on Via del Porrione, in the Terzo San Martino (named after this church) in central in Siena, region of Tuscany, Italy.
Adjacent to the church is the Renaissance style Logge del Papa erected in 1462 by commission by Pope Pius II Piccolomini.
The Baroque façade was built in 1613 and the bell tower completed in 1738.
[2] The interior, in the counterfaçade, has a canvas of the Immaculate Conception Protecting Siena during the 1526 Battle of Camollia 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 San Bartolomeo (1637) by Guercino and a Nativity by Domenico Beccafumi.