Abū Ḥāmid Muḥammad ibn Muḥammad al-Ghazālī (c. 1058–1111); (Persian: ابو حامد محمد ابن محمد غزالی‎), known as Al-Ghazali or Algazel to the Western medieval world, was a Muslim theologian, jurist, philosopher, and mystic of Persian descent.

Al-Ghazali has sometimes been referred to by historians as the single most influential Muslim after the Islamic prophet Muhammad. Within Islam he is considered to be a Mujaddid or renewer of the faith, who, according to tradition, appears once every century to restore the faith of the community. His works were so highly acclaimed by his contemporaries that al-Ghazali was awarded the honorific title "Proof of Islam" (Hujjat al-Islam). Others[who?] have cited his opposition to certain strands of Islamic philosophy as a detriment to Islamic scientific progress.[full citation needed] Besides his work that successfully changed the course of Islamic philosophy—the early Islamic Neoplatonism developed on the grounds of Hellenistic philosophy, for example, was so successfully criticised by al-Ghazali that it never recovered—he also brought the orthodox Islam of his time in close contact with Sufism. It became increasingly possible for individuals to combine orthodox theology (kalam) and Sufism, while adherents of both camps developed a sense of mutual appreciation that made sweeping condemnation of one by the other increasingly problematic.