His honorific is Abū'l-ʿAbbās. He served as the judge (qāḍī) of Shiraz. He compiled around 400 works. He was among the leading imams of the Shāfiʿī madhhab (school of law). He was given the nickname Bāzū'l-Ashhab (Bozdoğan, "the Grey Falcon"). He studied fiqh (Islamic jurisprudence) with Abū'l-Qāsim al-Anmāṭī, al-Muzanī, and other companions of the Shāfiʿī school. Through him, the Shāfiʿī madhhab spread to many regions of the Islamic world. We have recounted his biography in the "Ṭabaqāt al-Shāfiʿiyya". He passed away in the month of Jumādā al-Awwal of this year, having completed fifty-seven years and six months of age.
Ibn Khallikān said: "Aḥmad b. ʿUmar died on Monday, the twenty-fifth of Rabīʿ al-Awwal. At his death, he had completed fifty-seven years and three months. His grave is a place that is visited."