This monastery was founded in 1301 by Guzmán El Bueno, who rose to fame during the Conquest of Tarifa (1294). Since the 19C, it has been home to a women's prison, a brewery and a tobacco factory. The restored fortified edifice protects a double church, whose Gothic style reveals Languedoc and Mudejar influences from the Almohad era. Admire the 15C frescoes in the Patio de Evangelistas and the cloisters, as well as the altarpiece by Juan Martínez Montañés (17C) in one of the chapels.