The Church of Mary's Nativity of Castel del Piano is also known as the Provost Church or Opera's Church. Built between the XVII and XIX century, has a Latin cross plan. Each arm of the transept hosts a chapel. In its interior the following frameworks:
- The Madonna with the Child with Saint Catherine of Alexandria and other saints by Giuseppe Nicola Nasini (XVII century);
- Nativity of Mary (1706-1708) by Giuseppe Nicola Nasini;
- Pietà or Lamentation over the Dead Christ by Giuseppe Nicola Nasini, first half of eighteenth century;
- Madonna in Glory with SS. Niccolò and Michele Arcangelo, second half of XVII century by Francesco Nasini;
- San Cerbone, the Virgin and the Child, 17th century, attributed to the workshop of Rutilio Manetti, for some to the work of the son Domenico.