The historian Kamal Salibi surmises that successive Muslim atabegs (Turkic rulers) of Damascus resettled Mount Lebanon with Arab tribesmen to buttress the frontier with the Crusader states; the most prominent of the settler families were the branch of the Tanukh led by Ali ibn al-Husayn. The early 15th-century Buhturid chronicler Salih ibn Yahya noted that Ali's grandfather was a certain Abu Ishaq Ibrahim ibn Abi Abdallah, who was the commander of al-Bira in 1027. Salibi identifies al-Bira with the fortified town of al-Bira on the Byzantine-Islamic frontier in Anatolia where Ibrahim's clansmen and descendants had likely gained significant experience in frontier warfare; Abu Izzedin considers Salibi's theory incorrect and holds that al-Bira was the Gharb village of the same name mentioned in the Druzes' Epistle 48. Abu Izzedin further notes that the 1061 entry of the Sijill al-Arslani records the name Abu Ishaq Ibrahim ibn Abdallah as one of the three Tanukhid emirs addressed in Epistle 50 and places his death in 1029. The historian William Harris questions Salibi's theory of the Buhturids' origins and considers it more probable that the family was already established in the Gharb and was at least distantly related to the Arslan Tanukhids who were slain in 1110, though the family may have been reinforced by Druze settlers from the northern Levant.