 It was most probably founded by Froila Bermúdez, Bermudo's grandfather.He had inherited half of the monastery from his father, Pedro Fróilaz, and King Alfonso VII, who had been raised with Bermudo since Pedro had been his tutor, returned the other half of the monastery which Pedro Fróilaz had given him, so that Bermudo would have the entire property.He gave the monastery to his daughter Urraca (the elder) who entered the convent as a nun and later became its abbess.