Isḥaq of Nineveh, also remembered as Saint Isaac the Syrian, Isaac of Nineveh, Abba Isaac, Isaac Syrus and Isaac of Qatar, was a 7th-century Syriac Christian bishop of the Church of the East, and theologian best remembered for his written works on Christian asceticism. He is regarded as a saint in the Church of the East, Roman Catholic, Eastern Orthodox and Syriac Orthodox churches. His feast day falls, together with 4th-century theologian and hymnographer St. Ephrem the Syrian, on January 28. In the Syriac Orthodox Church, his feast day falls on May 14. 640 – 700; died at about 60. Alive at the same time as Alī ibn Abī Ṭālib, Brahmagupta, Uthman ibn Affan, Bede, and Charles Martel. Wiki link