Cath. (552–67), successor of Mar Aba I, in a period of tension between the Church and the Persian authorities. Yawsep is primarily known as the convener of the Synod of 554, a report of which is preserved in the Synodicon Orientale. Following an introductory narrative (in which Yawsep speaks in the 1st pers. sing., and refers to the internal and external problems faced by the Church) and a brief profession of faith (ET in Brock), the report contains 23 canons aiming at restoring order and discipline in the hierarchy of the church and warning against possible abuses by the cath., the bishops, the priests, and the laypeople. Even though the report reflects the difficult circumstances of Yawsep’s first years, there is no evidence of controversies surrounding the person of the cath. As a matter of fact, the E.-Syr. sources agree that during the first three years of his tenure Yawsep ruled with dignity. After three years, however, he is said to have become arrogant and to have given himself over to all sorts of misbehavior as well as to simony. This eventually led the metropolitans and bps. to depose Yawsep, with the consent of Emperor Khusrau, whose favor Yawsep had at first enjoyed. It is unclear whether Yawsep’s successor, Ḥazqiel, was appointed immediately after his deposal (567), or only three years later, after Yawsep’s death.

Bar ʿEbroyo, who appears to be well-informed about this episode, reports that ‘according to some’ Yawsep, upon his deposal, composed apocryphal letters under the names of Yaʿqub of Nisibis and Ephrem, written in support of Papa bar ʿAggai who, in the early 4th cent. had been deposed for reasons of abuse of power. Yawsep would thus have retrojected his own experience into that of Papa, claiming with the help of the forged letters that he, just like Papa, was innocent. It should be noted, however, that Yawsep cannot possibly have been the author of the entire dossier of the Papa letters, since some of them already existed, and were read, at the synod of Dadishoʿ (424).

A more positive note is appended to the lengthy discussion on Yawsep in the Chronicle of Siirt (185–86). The author quotes the historian Bar Sahde (ca. 600?) for noticing that when the plague struck, Yawsep devoted himself to burying the dead who were lying in the streets, adding Bar Sahde’s comment that this was Yawsep’s only meritorious deed. Finally, in a brief fragment, of uncertain origin, published by Mingana under the name of Barḥadbshabba (ET in Becker), Yawsep is portrayed as a strong opponent of the School of Nisibis, ‘which he hated’.