Complex sentence: In the 14th century, the Ayyubids rebuilt the castle of Hisn Kayfa which served as their stronghold as vassals of consecutively Mamluks and Dulkadirids until they were supplanted by the Ottoman Empire in the early 16th century.
Split into simpler sentences: In the 14th century, the Ayyubids rebuilt the castle of Hisn Kayfa which served as their stronghold. The Ayyubids of Hisn Kayfa were vassals of the Mamluks and later the Dulkadirids until being supplanted by the Ottoman Empire in the early 16th century.