Abū ʿAbdillāh Muhammad ibn Idrīs al-Shāfiʿī (Arabic: أَبُو عَبْدِ ٱللهِ مُحَمَّدُ بْنُ إِدْرِيسَ ٱلشَّافِعِيُّ‎, 767-820 CE) was an Arab Muslim theologian, writer, and scholar, who was the first contributor of the principles of Islamic jurisprudence (Uṣūl al-fiqh). Often referred to as 'Shaykh al-Islām', al-Shāfi'ī was one of the four great Sunni Imams, whose legacy on juridical matters and teaching eventually led to the Shafi'i school of fiqh (or Madh'hab).