Isfarayin

Isfarayin (Isfara'in), in the Khurasan region of northeastern Iran near Nishapur, was a medieval town of the Nishapur district. The Ash'ari theologian and heresiographer Abd al-Qahir al-Baghdadi (d. 1037), author of al-Farq bayn al-Firaq (The Difference between the Sects), settled and taught in Isfarayin, where he died.