Muslim legal scholar who played an important role in the formation of Islāmic legal thought and was the founder of the Shāfiʿīyah school of law. He also made a basic contribution to religious and legal methodology with respect to the use of traditions.

Little is known for certain of his life. He belonged to the tribe of the Quraysh, the tribe of the Prophet Muḥammad, to whom his mother was distantly related. His father died when he was very young, and he was brought up, in poor circumstances, by his mother in Mecca. He came to spend much time among the Bedouins and from them acquired a thorough familiarity with Arabic poetry. When he was about 20 he travelled to Medina to study with the great legal scholar Mālik ibn Anas. On Mālik's death in 795, ash-Shāfiʿī went to Yemen, where he became involved in seditious activities for which he was imprisoned by the caliph Hārūn ar-Rashīd at ar-Raqqah (in Syria) in 803. He was soon freed, however, and after a period of study in Baghdad with an important jurist of the Ḥanafī school, ash-Shaybānī, he went to al-Fusṭāṭ (now Cairo), where he remained until 810. Returning to Baghdad, he settled there as a teacher for several years. After some further travels, he returned to Egypt in 815/816 and remained there for the rest of his life. His tomb in al-Fusṭāṭ was long a place of pilgrimage.

During the course of his travels, ash-Shāfiʿī studied at most of the great centres of jurisprudence and acquired a comprehensive knowledge of the different schools of legal theory. His great contribution was the creation of a new synthesis of Islāmic legal thought. Most of the ideas with which he worked were already familiar, but he had the insight to structure them in a new way. Primarily he dealt with the question of what the sources of Islāmic law were and how these sources could be applied by the law to contemporary events. His book, the Risālah, written during the last five years of his life, entitles him to be called the father of Muslim jurisprudence.