Theologian, abbot, and solitary of the Ch. of E., who has been viewed as the systematizer of the mystical and ascetic life for the Syriac-speaking churches. The primary source for Yawsep’s life is ‘The Book of Chastity’ by Ishoʿdnaḥ of Baṣra (ca. 868–70). Yawsep was born to Persian Zoroastrian parents in the village of Nimrud early in the 8th cent. (ca. 710?). After the village rebelled against Caliph ʿUmar b. ʿAbd al-ʿAzīz (r. 717–20), the latter retaliated, and soldiers captured the seven-year-old Yawsep, eventually selling him as a slave to an Arab, then later to a Christian of Qardu in present-day northern Iraq. Impressed by the life of the monks of the nearby monastery of Yoḥannan of Kamul, Yawsep asked to be baptized and was allowed to enter at a young age into the monastery of Abba Ṣliba in Beth Nuhadra in northern Iraq. After the obligatory novitiate in the cenobitic community, Yawsep established himself as a hermit in Qardu for a number of years. Later he was made the head of the monastery of Mar Bassima, also in Qardu, but eventually he returned to the eremitic life in the mountain of Zinai in Adiabene of northeast Iraq. In the neighborhood of his hermitage was another monastery, that of Rabban Bakhtishoʿ, and before long Yawsep was persuaded to become their abbot, remaining until his death. ʿAbdishoʿ bar Brikha (d. 1318) said that Yawsep had written an incredible number of works, 1900 in total, but only ten were extant by ʿAbdishoʿ’s time. His most systematic work, ‘A letter on the three stages of the monastic life’, was not positively identified as his work until the last thirty years. In the ms. tradition it was attributed to Philoxenos of Mabbug, but a number of items in and about the text had raised questions about its authorship for quite some time. A synod called in 786–787 by the patr. of the Ch. of E. Timotheos I condemned a trio of writers — Yoḥannan Iḥidaya, Yoḥannan of Dalyatha, and Yawsep Ḥazzaya — for some of their theological ideas. Yawsep was accused of messalianist tendencies, supposedly claiming that it is necessary to reject prayer and the office in order to receive the gifts of the Spirit. Allied to this is the alleged doctrine that the gmirā (the perfect or mature person) no longer has any need of active prayer, the offices, reading, or manual labor. Neither charge has any substantive foundation in the known writings of Yawsep. The synod denied the possibility of perfection for human nature, except for that of Christ.