Following the devastation of the urban centers of Mesopotamia at the hands of Timur, a military leader operating under the guise of restoring the Mongol Empire, he was known as "the Sword of Islam." His conquest of Baghdad and the general area, especially the destruction of Tikrit, affected the Syrian Orthodox Church which sheltered near Nineveh at Mar Mattai Monastery. Following the destruction of Christians in the region, the Ismailis and Sunni and Shi'a Muslims was attacked indiscriminately by Timur during the second part of the 14th century.