Imam Abu Dawud al-Sijistani أبو داود سليمان بن الأشعث السجستاني

Imam Abu Dawud Sulayman ibn al-Ash'ath al-Sijistani rahimahullah (202-275 AH / 817-889 CE) was born in Sijistan in present-day eastern Iran and rose to become one of the most eminent hadith scholars of the third Islamic century. He studied under Imam Ahmad ibn Hanbal in Baghdad - alongside contemporaries such as al-Bukhari - and traveled extensively to the major centers of hadith transmission across the Islamic world. Among his teachers were leading scholars of his era, and among his students were luminaries such as al-Tirmidhi and al-Nasa'i. From over 500,000 hadiths he encountered in his travels, he carefully selected fewer than 5,000 for inclusion in his Sunan, making it the most focused of the Six Books (al-Kutub al-Sitta) on ahadith al-ahkam - the narrations from which legal rulings are derived. He taught the Sunan in Baghdad and other major cities. His famous letter to the people of Makka explaining his principles of hadith selection became a foundational document in the science of hadith criticism.