The church of Sant’Agostino, located on the Prato di Sant’Agostino, is one of Siena’s most important sacred buildings, both from the architectural and the art-historical points of view, thanks to the great number of masterpieces it contains.
Building began in 1259 when some Hermits of Saint Augustine, after official recognition of their order by Pope Alexander IV, bought for 220 lire two pieces of land on the so-called “Saint Agatha’s Hill” in front of the Porta dell’Arco, where the church now stands. Work moved very slowly for more than fifty years, supported by donations from the Commune of Siena, Santa Maria della Scala hospital, and private citizens.
In the late thirteenth century, perhaps because the church was too small, the friars decided to build a transept between the nave and the high altar, making it necessary to build a crypt underneath it to bear the weight of the new structure.
It is difficult to say exactly when construction ended, but the building had to have already been finished by August 1398, since documents tell us that a windstorm caused half of the bell tower to fall down; with its forty meters of height, it was one of the tallest towers in the city.
However, the Augustinians were not completely satisfied with this church, and they asked the Commune for more money to add some chapels to enlarge the existing building.
In April 1479, because of the plague that was raging through Siena at the time, the Augustinians and many other religious were given an offering of 20 lire so that they would present “countless prayers and supplications to rid the city of the plague.” The friars used this money to finish the work on the choir area, the transept, and the underlying crypt.
Subsequently, the Augustinians attempted to embellish the church with works by the best artists over the centuries, but unfortunately some of these works were destroyed by a fire in 1747. Thus an expensive restoration of the church was initiated, costing around 10,000 scudi, on a design by the architect Luigi Vanvitelli sent specifically by the general of the Augustinian order in Rome to Siena.
In 1818 the church was part of a larger project to remodel the adjacent convent with the construction of the porch in front, designed by the architect
Agostino Fantastici, and the demolition of the old bell tower. The church was definitively abandoned by the Augustinians in 1972. Today, the building is used during celebrations for the feast of Saint Rita on 22 May and for concerts of sacred music.