St. Isaac was born in the region of Qatar on the western shore of the Persian Gulf. When still quite young, he entered a monastery with his brother. His fame grew as a holy man and teacher. He was subsequently ordained bishop of Nineveh, the former capital of Assyria to the north, but requested to abdicate after only five months.
He then went south to the wilderness of Mount Matout, a refuge for anchorites. There he lived in solitude for many years studying the Scripture, but eventually blindness and old age forced him to retire to the monastery of Rabban Shabur, where he reposed and was buried. His feast day is January 28.