al-Wahidi

Abu al-Hasan Ali ibn Ahmad al-Wahidi was a Qur'an commentator and philologist of Nishapur, a major center of learning in Khurasan (north-eastern Iran) under the Seljuk Turks. His family were merchants who, according to the biographers, had originally come from Saveh, between Rayy and Hamadhan; the name "al-Wahidi" is usually traced to a forebear, al-Wahid. Al-Wahidi spent his career in Nishapur, where he studied tafsir (Qur'anic exegesis) with the celebrated commentator al-Tha'labi, hadith (Prophetic reports) with Abu Uthman al-Sabuni, and Arabic grammar and prosody with al-Arudi. Biographers single him out as al-Tha'labi's outstanding pupil.

He is best remembered for two contributions. First, his three graded Qur'an commentaries — al-Basit (the extensive), al-Wasit (the medium), and al-Wajiz (the brief) — pitched at different levels of reader, a tiered model later imitated by others. Second, his Asbab al-Nuzul ("Occasions of Revelation"), the earliest surviving systematic collection of the reported circumstances in which particular Qur'anic verses were revealed; it became the standard reference for that genre. Modern scholarship describes him as the last major figure of the "Nishapuri school" of exegesis.

Al-Wahidi enjoyed the patronage of the powerful Seljuk vizier Nizam al-Mulk, and later that of the vizier's brother. He followed the Shafi'i school of law; sources also associate him with Ash'ari theology. He died after a lingering illness on 2 Jumada II 468 AH (January–February 1076) in Nishapur.