(1201–74 (AH 598–673)). Shi‘ite scholar and theologian. Born in s (hence the name), he worked under an Ism ‘ l ruler in Alam t (the centre for the Assassins ), and wrote Ism ‘ l works of accepted and great authority, but his own personal allegianace is uncertain. He compiled the astronomical tables known as Z j al-Kh n , and introduced into astronomy ‘the s