BEHA UD-DIN (ABU-L-MAHASIN YUSUF IBN RAF T` IBN SHADDAD BEHA UD DIN) (I145--1234), Arabian writer and states man. He was at first a teacher in the Nizamiyya at Baghdad and then professor at Mosul. In 1187, of ter making the pilgrimage to Mecca, he visited Damascus. Saladin, who was at the time besieg ing Kaukab (a few miles south of Tiberias), sent for him and became his friend. Beha ud-Din observed that the monarch was engrossed by the war which he was then waging against the enemies of the faith, and sought his favour by urging him to its vigorous prosecution. With this view he composed a treatise on The Laws and Discipline of Sacred War, which he presented to Saladin. From this time he remained constantly attached to the person of the sultan, and was employed on various embassies and in departments of the civil government. He was appointed judge of the army and judge of Jerusalem. After Saladin's death Beha ud-Din remained the friend of his son Malik uz-Zahir, who ap pointed him judge of Aleppo. Here he employed some of his wealth in the foundation of colleges. When Malik uz-Zahir died, his son Malik ul-`Aziz was a minor, and Beha ud-Din had the chief power in the regency, using it for the patronage of learning. He lived in retirement after the abdication of Malik ul-`Aziz. His chief work is his Life of Saladin (English trans. the Palestine Pilgrims' Text Society, London, 1897).