The moment
Abū Ḥāmid al-Ghazālī, chief professor at Baghdad's Niẓāmiyya, left his post in 1095 after a crisis of certainty, lived for years as a Sufi and wrote The Revival of the Religious Sciences. He is widely credited with making Sufism acceptable within Sunni orthodoxy.
People: al-Ghazālī, Niẓām al-Mulk, Ibn Rushd (Averroes)