Basilica of Saint Mary of the Angels

The idea of transforming the principal section of the Diocletian Baths into a church goes back to Giuliano da Sangallo and Baldassare Peruzzi (1515 ca.), but in the end it was Michelangelo who carried out the design and Jacopo del Duca who built it (1561-66). As legend has it, the reason which prompted Pius IV to commission such a work was that many christian martyr were forced to labor at building the baths.

In the 1700s, the church underwent another transformation completed for the Jubilee of 1750 by Luigi Vanvitelli, which gave the church its current look, especially the interior. In 1727, the altar piece of Saint Peter's Basilica was transferred here, replaced by a mosaic copy at the Basilica of the Vatican.