Metropolitan of Prat d-Mayshan (Baṣra) and author. His Ktābā d-nakputā ‘Book of Chastity’ (Liber Castitatis) concerns monastic foundations, mostly of the late Sasanian and early Arab periods. The work consists of 140 short notices about monastic figures, mostly founders of monasteries, beginning with Mar Awgen (traditionally dated to the 4th cent.) and continuing until the mid 9th cent. It has also been suggested (by Nautin) that he was the author of the Chronicle of Siirt , which survives only in Arabic (ed. A. Scher, in PO 4.3 [1907], 5.2 [1910], 7.2 [1910], and 13.4 [1918]); though it is not impossible, the suggestion remains doubtful. Ishoʿdnaḥ is also the author of a long poem (unpublished) on Mar Yawnan, founder of a famous monastery near al-Anbār . Several further works by him, including an Ecclesiastical History and a treatise on logic, have not been preserved.