Later on Sancho el Mayor of Navarra, King of Navarra, introduced Cluny´s Benedictine rule, adopting new reforms in the Monastery that caused a new consecration in 1049. Soon after the Monastery became the royal pantheon of the Kingdom of Aragón.

Being the first to adopt it, the Monastery played an important role in the introduction of the Cluniac reform. Cluny´s ecclesiastical and political suggestions had a great influence on society at that time.

The Monastery comprises two levels. The first level is situated right below a giant rock that seems to have swallowed the monastery. The cloisters on the terrace are unroofed, but the rock overhanging the columns provides a firm roof. This creates an atmosphere of fortitude and mystery that explains the perseverance of the monks of that time.

The capitals of the columns at the cloisters display sculptures created by an anonymous artist. They represent stories from the Bible and the lifes of some characters from the Gospel. The figure of the Inmaculada Concepción is worthy of note for the intensity reflected in the eyes. There are also sculptures of vegetal figures, with bulbous forms, curly stems with leafs... The compositions fill all the available room and adapt subtly to the form of the capitals.