The construction of the Church of Sant'Agostino was initiated in 1299 by the Augustinians, who had permanently settled in the town. The Church was designed to replace the Church of S. Pietro all’Orto, which wasn’t big enough to host the constantly growing population of the city.
The first construction works were completed in 1312, while the apse and the side chapels were built in the XIV century.
Extremely interesting is the side chapel of Santa Lucia, built in 1348 by the silversmiths of Massa, for whom she was the patron saint.
The complex was completed at the beginning of the XV century with the construction of the cloister.
The Church houses the remains of San Bernardino da Siena, who, despite his name, was born in Massa Marittima in 1380.
The construction of the cloisters, which were part of the convent of the Augustinian monks, started in 1410.