al-Bayhaqi

Abu Bakr Ahmad ibn al-Husayn al-Bayhaqi (born Ramadan 384 AH / 994 CE) was among the most important Sunni scholars of hadith — the recorded reports of the sayings and deeds of the Prophet Muhammad — in the eastern Islamic world. He was born in the town of Khusrawjird near Sabzevar, in the district of Bayhaq (from which he takes his name) in Khurasan, a region of present-day northeastern Iran.

In law he followed the Shafi'i madhhab (one of the four main Sunni schools of jurisprudence), and in creed he is counted among the Ash'ari school of theology (kalam, speculative theology). He studied hadith under leading masters of Nishapur, above all al-Hakim al-Naysaburi, whose foremost pupil he is traditionally said to have been, and he travelled through Khurasan, Iraq and the Hijaz (western Arabia) gathering reports.

He is best known as a compiler. His al-Sunan al-Kubra ("The Great Collection of Traditions") is one of the largest topically arranged hadith works in the tradition, and his Shu'ab al-Iman ("Branches of Faith") gathers reports on the moral and devotional life. Both are widely cited and were prized for his care in noting the strength or weakness of chains of transmission.

He spent most of his life teaching and writing in Bayhaq, and was later called to Nishapur. He died on 10 Jumada al-Ula 458 AH (9 April 1066); his body was carried back to Bayhaq for burial. Sources differ on whether he was 72 or 74 at his death.