Teacher of biblical interpretation at the School of Nisibis. Yoḥannan was a relative of Abraham of Beth Rabban and both he and Abraham were probably related to Narsai, the first director of the School of Nisibis and the ‘master’ (rabbān) who is referred to in the second part of both their names. Yoḥannan may have served as an assistant or a co-administrator to Abraham during the latter’s tenure as head of the School. It is noteworthy, however, that Barḥadbshabba the historian, our main source on Abraham, does not mention Yoḥannan’s name at all, while the other Barḥadbshabba, the author of the Cause, emphasizes Yoḥannan’s significance in the School.

Like Abraham, Yoḥannan is credited with biblical commentaries, none of which have survived. He is regularly quoted, however, by later E.-Syr. biblical commentators. In one of his letters (no. 9), Patr. Timotheos I is probably referring to Yoḥannan’s commentary on Leviticus when he tries to dissuade his correspondent from understanding Yoḥannan’s interpretation of Lev. 18:18 as allowing a Christian to marry his wife’s sister after the death of his wife, a practice which Timotheos strongly opposed.

Outside the field of biblical interpretation, Yoḥannan is said to have authored treatises against the Jews, and against the Eutychians (Barḥadbshabba) or the Magi (Chronicle of Siirt), along with discourses, one of which dealt with the Persian emperor Khusrau (r. 531–78), either when he gained control over Nagran (572) or at his death. Since, however, Barḥadbshabba situates Yoḥannan’s death during the plague which raged in Northern Mesopotamia in the first half of the 560s, we are left with a chronological problem here, reminding us of how little is known about this intriguing figure.