a Sunni Islamic scholar , Sunni Islamic philosopher, Sunni theologian and logician.
He lived during the troubled times of the Mongol invasions. He was a member of the school founded by Ahmad ibn Hanbal, and is considered by his followers, along with Ibn Qudamah, as one of the two most significant proponents of Hanbalism; in the modern era, his adherents often refer to the two as "the two sheikhs" and Ibn Taymiyyah in particular as "Sheikh ul-Islam". Ibn Taymiyyah was notable for having sought the return of Sunni Islam to what he viewed as earlier interpretations of the Qur'an and the Sunnah, and is considered to have had considerable influence in contemporary Wahhabism, Salafism, and Jihadism. He is renowned for his fatwa issued against the Mongol rulers declaring jihad by Muslims against them compulsory, on the grounds that they did not follow Sharia and as such were not Muslim, their claims to have converted to Islam notwithstanding. His teachings had a profound influence on the Muhammad ibn Abd al-Wahhab, and other later Sunni scholars