George Makdisi theorizes that the "ijazah" issued in medieval Islamic madrasas in the 9th century was the origin of the doctorate that later appeared in medieval European universities. Alfred Guillaume, Syed Farid al-Attas and Devin J. Stewart agree that there is a resemblance between the "ijazah" and the university degree. However, Toby Huff and others reject Makdisi's theory. Devin J. Stewart finds that the "ijazat al-ifta", license to teach Islamic law and issue legal opinions, is most similar to the medieval European university degree in that it permits entry into certain professions. However, a key different is that the granting authority of the "ijaza" is an individual professor whereas the university degree was granted by a corporate entity.