Al-Ghazali is one of the greatest Islamic theologians and mystic al thinkers. He learned various branches of traditional Islamic religious sciences in his home town of Tus, Gorgan and Nishapur in the northern part of Iran. He was . involved in Sufi practices from an early age. Being recognized by Nizam al-Mulk , the vizir of the Seljuq sultans, he was appointed head of the Nizamiyyah College at Baghdad in AH 484/1091 CE. As the intellectual head of the Islamic community, he was busy lecturing on Islamic jurisprudence at the College, and also refuting heresies and responding to questions from all segments of the community. Four years later, however, al-Ghazali fell into a serious spiritual crisis and finally left Baghdad , renouncing his career and the world After wandering in Syria and Palestine for about two years and finishing the pilgrimage to Mecca , he returned to Tus, where he was engaged in writing, Sufi practices and teaching his disciples until his death. In the meantime he resumed teaching for a few years at the Nizamiyyah College in Nishapur.