Complex sentence: According to Arab sources, the site of Margat Castle was first fortified in 1062 by Muslims who continued to hold it within the Christian Principality of Antioch in the aftermath of the First Crusade.
Split into simpler sentences: According to Arab sources, the site of Margat Castle was first fortified in 1062 by Muslims. They continued to hold it within the Christian Principality of Antioch in the aftermath of the First Crusade.