Author, monk, and solitary, abbot of the Monastery of the Cross (Dayr al-Ṣalīb) near Ḥaḥ (ca. 1462/3–1480/1), bp. for the Monastery of Mor Quryaqos in Hezza near Zargel and Ḥesno d-Kifo (1480/1) with the name Basil. Afram Barsoum identifies him with the Patr. Masʿūd of Ṭur ʿAbdin (d. 1509). Masʿūd was a vigorous promotor of monastic life in Ṭur ʿAbdin. He is the author of the elpo ruḥonoyto ‘the Spiritual Boat’, a work intended to guide monks and solitaries to the ‘haven of impassibility’. Written in the dodecasyllable meter, it is essentially an ascetical and mystical treatise. It is divided into three parts, on trinity, on christology and on the divine gifts and virtues distributed by Christ to the Angels and human beings. The third part is based indirectly on the Celestial Hierarchy of Pseudo-Dionysius the Areopagite. As a patr. he appointed a maphr. and twelve bishops for Ṭur ʿAbdin, which caused much confusion. According to Barsoum, some senior bishops denounced him to the patr. of Antioch. Masʿūd had to step back for some time, but was again in function by the end of his life. According to the continuator of Bar ʿEbroyo’s Ecclesiastical History, these senior bishops denounced him however to the Emir of Ḥesno d-Kifo, who confined him to a monastery. As a result he abdicated and ordered his followers not to appoint a new patr. of Ṭur ʿAbdin.

The main source of Masʿūd’s life till his episcopal ordination is a short note written by his disciple ʿAziz which is preserved in the oldest ms. of the Spiritual Boat, now kept in Baghdad. According to this note Masʿūd composed some other writings, which do not seem to have been preserved.