Cath. He was the son of a certain Ishoʿ in Baghdad , and he became bp. of Zabe between 884 and 891. In the summer of 900 he was consecrated cath. He died on 16 May 905. A few canons of a synod that he convened in October 900 are quoted in the Nomocanon of ʿAbdishoʿ bar Brikha . The rest of the canons are preserved in Arabic translation only. In Syriac Yoḥannan authored ‘Canons and admonitions (zuhhāre) of the altar service’; in Arabic a treatise on ‘Principles’ (fi al-usūl) and a Letter on the Fast of the Ninevites. In addition, a work on ‘Juridical decisions and rules for division of inheritance’ based on Islamic law is attested for him. This may perhaps be identical with a collection known in present-day scholarship as ‘Syriac texts on Islamic Law’, which is transmitted in both the E.- and W.-Syr. tradition as well as in an Arabic translation. While a marginal note in the Arabic translation attributes the work to Yoḥannan, the E.-Syr. mss. transmit it anonymously, and W.-Syr. mss. attribute it either to a Patr. Yuḥanon (whose identity cannot be ascertained) or to ‘Mor Ignatius and Mor Yuḥanon’. Its authorship, therefore, remains uncertain.