The castle was built largely during the 11th and 13th centuries, when its position on the frontier between Christian and Muslim lands gave it strategic importance. The first of the two major building programs began circa 1020, when Sancho el Mayor (r. 1063–94) reconquered the surrounding lands from the Muslims.

 A distant view of the complex in 2005

After 1070, Loarre became increasingly important. In 1073, King Sancho Ramírez installed a community of Augustinian canons, and it was from Loarre that he prepared for the conquest of Huesca in 1094. In 1097, however, his successor, Peter I of Aragon and Navarre, donated all the goods of Loarre to a new royal monastery at Montearagon. This evidence suggests that the second major construction program was undertaken between 1073 and 1097, and much building evidently does date from this period. By comparison with other monuments, however, it is also clear that the building and decorative program continued into the 12th century.

The location appears in the 2005 epic film Kingdom of Heaven.[1]