This monastery was built on the site of a small chapel known as Egica. Construction was carried out by apprentices of Master Mateo with very similar ornamental patterns to the ones in the Cathedral of Santiago. The monastery fell into decline with the ecclesiastical confiscations of the 19th century and it became a private property. A masonry bridge was built to access the site over the Deza River, which measures almost 15 m high and 10 m wide. Today the monastery is considered a gem of the Galician pointed Romanesque style and a symbol of the region of Deza. It was founded in 939 by Counts Gonzalo and Teresa, and in the late 10th century it was destroyed and then rebuilt. It experienced a period of prosperity in the 11th and 12th centuries. There is a Latin inscription bearing the date 1171 inside the church, which was probably the year it was built by Abbot Fernando and the monks. This means the church was built in the late 12th century and probably completed in the 13th century. The nave is composed of three sections separated by columns with capitals with vegetal motifs. The east facade is particularly impressive due to the three apsidal chapels at the east end, supported on the large pedestal of the crypt.