Construction of this National Monument, also known as 'the Galician El Escorial', began during the second half of the 12th century. The departure of the monks in 1835 and their return in 1929 are the monastery's two most important historic moments. The church, with Gothic and Baroque elements, is the most important part of this monumental site. The Renaissance contribution can be seen in the sacristy, in the Bishop's Staircase and in the Courtyard of the Pinnacles. The courtyards of los Caballeros and Medallones are in the Baroque style; as is the Great Honour Staircase. In 1989, the European Union gave the monks the 'Europa Nostra' prize, after having carried out the restoration of the building themselves.