Abu Ya'la al-Farra'

Muhammad ibn al-Husayn al-Farra', known as Abu Ya'la (380–458 AH / 990–1066 CE), was the foremost Hanbali scholar of 5th-century AH Baghdad. He served as chief judge of Baghdad. His al-Mu'tamad fi Usul al-Din (The Relied-Upon in Principles of Religion) is an important Hanbali theological work. His al-Ahkam al-Sultaniyyah (Sultanical Rulings) is a significant work on Islamic political theory and public law. He played a crucial role in developing the Hanbali school's systematic approach to theology and jurisprudence and trained many important scholars including his student al-Qadi Abu Ya'la.