 The Arab chroniclers of physicians indicate that Isaac Israeli served as a doctor to Ubayd Allah al-Mahdi, the founder of the Fatimid Dynasty of North Africa, who reigned from 910–934. In his capacity as physician, Israeli wrote several medical treatises which were widely regarded in the Islamic world, and highly valued in Christian scholastic circles as well. These works include the Book of Fevers, the Book of Foodstuffs and Drugs, and the Book of Urine. Later Islamic historians relate accounts that the first and third Fatimid rulers died from not following the sound advice of Isaac Israeli, though the absence of these anecdotes in the earlier chronicles, combined with their literary trope-like character, render the tales suspect. Nonetheless, these narratives do indicate the great respect accorded to Isaac Israeli.