This monastery was founded in the 9C and is a symbol of the continuation of the Christian faith during the Muslim occupation. It was chosen as a pantheon by the kings and noblemen of Aragon-Navarre. In the 17C, another monastery was built higher up. The oldest elements thus remain at the lower level: the lower church is one of the few surviving Mozarabic buildings in the region. The pantheon courtyard of Aragon noblemen (11C-14C), the upper church (with the royal pantheon) and the cloister are set in the upper part.