Bp. of Mabbug (Hierapolis northeast of Aleppo) at the beginning of the 7th cent.; diplomat and Bible translator of excellent Greek education. Only one exact chronological date is transmitted (his translation of the NT 615/16), but his activities on the official stage of his Church link him with persons and events of his time and provide a general idea about the chronology of his life. Bar ʿEbroyo, Ecclesiastical History (I, 50 = vol. 1, col. 267) and Michael Rabo, Chronicle (X, 25 = vol. 4, 391) give a summary of his career: Born at Heraclea (Ḥarqel) in the Euphratensis (northwest of Mabbug) he pursued Greek studies in his youth at the Monastery of Qenneshre (on the Euphrates) and became a monk in the monastery of Tarʿil (in the same region), subsequently bp. of Mabbug. He was expelled from his see by the Chalcedonians and fled to Alexandria (Egypt) where he translated the NT. His Greek education qualified him not only for the translation work but also to serve his Church on the ‘ecumenical’ scene. He doubtless could speak Greek fluently and was engaged in the negotiations with the Egyptian (Coptic) Miaphysites and with the Chalcedonians.

His life is linked with Dometianus (ca. 550–602), the nephew of the Byzantine emperor Maurice (582–602), who was appointed Chalcedonian bp. of Melitene (Malatya) by his uncle in ca. 580. In 598/99 this Dometianus started a persecution of the Miaphysites in the Orient, which made Tumo and other bps. (among whom was possibly Pawlos of Tella) flee to the Enaton, a monastic district nine miles outside of Alexandria (Michael, Chronicle, X,23 = vol. 4, 386). We do not know if he returned after the death of Dometianus when the Persians invaded the Byz. East and favoured the Miaphysites (but also the Ch. of E.) by expelling the Chalcedonian bishops (Bar ʿEbroyo, Ecclesiastical History, I,50 = vol. 1, col. 265; Michael, Chronicle, X,25 = vol. 4, 391).

In 615–6 he was at the Enaton, now linked with his Patr. Athanasios I Gamolo of Antioch (594–631). Tumo was his ‘Synkellos’ and diplomat who shared his efforts to reunite with the Egyptian (Coptic) Miaphysites after decades of schism dating from the time of his predecessor Peter of Kallinikos (581–91). The exile of the Syriac bishops in Egypt during the persecution might have invited the Miaphysites to reunite, but the actual negotiations were initiated by the Byzantine notable Nicetas and favoured by the Emperor Heraclius (610– 641) for political reasons. After the reunion of the Coptic and Syrian Miaphysites succeeded in 616 (Bar ʿEbroyo, Ecclesiastical History, I,50 = vol. 1, col. 269; Michael, Chronicle, X,26 = vol. 4, 392–9; ‘History of the Patr.’, ed. B. Evetts, 480–3), Athanasios gave an extensive report to Bp. Quryaqos of Amid (Diyarbakır). This letter (Michael, Chronicle, X,26 = vol. 4, 392–9) reveals that both patr. were not present in person and that Tumo was appointed speaker of the Syrians and charged with the negotiations.

When the Persians conquered Egypt and devastated the Enaton (619/20), Tumo and his version escaped destruction. After 627 the Persian power faded, and the victorious Emperor Heraclius was in a strong position when in 631 he met with Athanasios and twelve of his bishops (Tumo among them, according to Michael) at Mabbug to discuss a christological formula for union (Bar ʿEbroyo, Ecclesiastical History, I,50 = vol. 1, col. 271–73; Michael, Chronicle, XI,3 = vol. 4, 409–10). But no agreement was reached, and severe restrictions for the Miaphysites followed. In those days Tumo was about sixty years old, he died ca. 640. An anonymous Syriac account of Tumo’s life (Assemani, BibOr, vol. 2, 90–2) confuses him with Tumo of Germanicea of the 6th cent.