Jacob of Nisibis – Our Righteous Father Jacob of Nisibis, also James of Nisibis , Jacob the Great , Jacob of Mygdonia ,[note 1] or Mor Ya`qub , called the “Moses of Mesopotamia”[1][2] for his wisdom and wonderworking abilities, was the second bishop of Nisibis,[note 2] spiritual father of the renowned Syriac writer and theologian Ephrem the Syrian, celebrated ascetic and one of the 318 fathers of the First Ecumenical Council at Nicaea.

Jacob of Nisibis – OrthodoxWiki

https://orthodoxwiki.org/Jacob_of_Nisibis

Our Righteous Father Jacob of Nisibis, also James of Nisibis , Jacob the Great , Jacob of Mygdonia ,[note 1] or Mor Ya`qub , called the “Moses of Mesopotamia”[1][2] for his wisdom and wonderworking abilities, was the second bishop of Nisibis,[note 2] spiritual father of the renowned Syriac writer and theologian Ephrem the Syrian, celebrated ascetic and one of the 318 fathers of the First Ecumenical Council at Nicaea.