Its construction dates back to the 14th century and was probably built on the site of an ancient Arab mosque. It has been classified as a Property of Public Interest since 1984. The interior has three naves with arcades supported by elegantly decorated columns. The high altar, covered with 17th-century tiles, is the pantheon of the Mello family; here rests D. Guiomar de Mello, the chief lady-in-waiting to the Spanish emperor Carlos V and lady-in-waiting to King Philip II. The ceiling of the central nave is decorated with a beautiful 18th-century painting.