9th-century clergy

'''Al-Shafi'i''' (; ;767–820 CE) was a Muslim scholar, jurist, muhaddith, traditionist, theologian, ascetic, and eponym of the Shafi'i school of Sunni Islamic jurisprudence. He is known to be the first to write a book upon the principles of Islamic jurisprudence, having authored one of the earliest work on the subject: al-Risala. His legacy and teaching on the matter provided it with a systematic form, thereby "fundamentally influencing the succeeding generations which are under his direct and obvious impact," and "beginning a new phase of the development of legal theory."