While scholars largely agree that his ethnic background is not knowable, Al-Farabi has also been described as being of either Persian or Turkic origin. Medieval Arab historian Ibn Abi Usaibia (died in 1270)—one of al-Farabi's oldest biographer—mentions in his Uyun that al-Farabi's father was of Persian descent. Al-Shahrazuri, who lived around 1288 and has written an early biography, also states that al-Farabi hailed from a Persian family. According to Majid Fakhry, an Emeritus Professor of Philosophy at Georgetown University, al-Farabi's father " was an army captain of Persian extraction. " A Persian origin has been stated by many other sources as well. Dimitri Gutas notes that Farabi's works contain references and glosses in Persian, Sogdian, and even Greek, but not Turkish. Sogdian has also been suggested as his native language and the language of the inhabitants of Farab. Muhammad Javad Mashkoor argues for an Iranian-speaking Central Asian origin. According to Christoph Baumer, he was probably a Sogdian. According to Thérèse-Anne Druart, writing in 2020, "Scholars have disputed his ethnic origin. Some claimed he was Turkish but more recent research points to him being a Persian."