ISÒ' JAHB II. - Nestorian Katholikós, born at Gêdâla, consecrated in 628 and died between 643 and 644. In a time troubled by wars between the Persians and Heraclius and by the Arab invasion, he gave an example of uncommon skill. He presented himself before Heraclius at Aleppo and, after obtaining certain concessions regarding the decrees of the Council of Chalcedon, he was able to communicate in sacred rites with the Byzantines, which earned him reproaches from the zealous Nestorians. Then, before the advance of the Muslims, he withdrew to Karkâ dê Bêt Sêlôk. I. left several writings of secondary interest.
BIBL.: A. Baumstark, Geschichte der syrischen Literatur, Bonn 1922, pp. 195-196.