Ajloun Castle (قلعة عجلون) Qalʻat ‘Ajloun, is a 12th-century Muslim castle situated in northwestern Jordan. It is placed on a hilltop belonging to the Mount Ajloun district, also known as Jabal ‘Auf after a Bedouin tribe which had captured the area in the 12th century. From its high ground the castle was guarding three wadis which descend towards the Jordan Valley. It was built by the Ayyubids in the 12th century and enlarged by the Mamluks in the 13th. The name ‘Ajlun goes back to a Christian monk who lived on this mountain in the Byzantine period. The castle stands on the ruins of a monastery, traces of which were discovered during archaeological excavations.