[6] Isaac became a monk at the nearby Mar Mattai Monastery, where he and his uncle George were both ordained as priests in 1669 by his tutor, Basil Yeldo, Maphrian of the East.
[7] In 1673, Isaac and George aided Basil Yeldo in renovating the Mar Mattai Monastery, for which they were fined and imprisoned by the wali of Mosul for a short while.
[10] In April 1687, Isaac was ordained as Maphrian of the East at the Great Church of Mardin by his uncle George, who had been elevated to patriarch of Antioch at the same time, upon which he assumed the name Basil.
[13] In 1701, he received permission from the Ottoman sultan to rebuild the churches of Mardin after having travelled to Constantinople and other places, accompanied by the priest Shukrallah.
[6] A synod was thus held at the Mor Hananyo Monastery in 1709, presided over by Maphrian Basil Lazarus of Tur Abdin, and Isaac was unanimously chosen to succeed George as patriarch of Antioch.