The Abbey of San Bartolomeo di Sestinga is in Vetulonia, part of the municipality of Castiglione della Pescaia, at the foot of the Badia Vecchia hill.
The original monastery was founded in the 11th century, and in the 12th century it was moved to the town Il Convento, where even today large ruins can still be found.
The founder of the monastery was an aristocrat from Lucca, Ranieri del fu Roffrido, present at the monastery in 1006 and whose family had numerous plots of land in the area. The site was important until the middle of the 13th century, when it passed to the Augustinian hermits and its decline began.The Augustinians, ignoring its heritage and ridding the monastery of its long-established political and economic status, reduced the abbey to solely a spiritual centre. As such it survived with difficulty until 1503, when Pope Alexander VI brought it under the jurisdiction of the Convent of Sant’Agostino in Siena.
In the 18th century, the church, already useless due to its distance from the village, was dilapidated, so much so that the Augustinians wished for its demolition, which was subsequently denied by the bishop of Grosseto. By the end of the century the monastery was transformed into a farm and the church was reduced to a warehouse. When the abbey was suppressed by Leopold II, the abbey’s goods were pledged to the residents of Vetulonia, with the aim of improving the economy in the local area.