Barsauma (Syriac: ܒܪܨܘܡܐ, Barṣaumâ) was Metropolitan of Nisibis in the 5th century, and a major figure in the history of the Church of the East. A capable politician, he was on good terms with Peroz I, King of the Sassanid Empire of Persia, and wielded great influence in the Church of the East. As such he was frequently in conflict with the Catholicos, or Patriarch, of the Church, first Babowai and then Acacius. Under his leadership the church moved away from Roman loyalties and became increasingly aligned with the Nestorian movement, declared heretical in the Roman Empire.
Barsauma had been a teacher at the School of Edessa early in his career, where his mentor had been Ibas. Barsauma was expelled with Ibas and other churchmen for their support of Nestorian teachings, declared heretical at the First Council of Ephesus in 431. Though Ibas was acquitted of heresy at the Council of Chalcedon in 451, following his death in 457 his associates found themselves expelled from their positions once again. Barsauma and other of Ibas' followers relocated to Sassanid Persia, where the persecuted local church had declared itself independent of all other churches.
Barsauma became metropolitan of Nisibis, one of the five great archdioceses of the Church of the East. He quickly became a favorite of King Peroz I, who preferred his compliant stance to that of Babowai, Catholicos of Seleucia-Ctesiphon and head of the Persian Church, whom he regarded as a pro-Roman traitor. Over time Barsauma and Babowai's relationship grew openly antagonistic. Barsauma was instrumental in Babowai's downfall, ultimately leading to the latter's execution by Peroz in 484.
Following Babowai's death, Barsauma became the most powerful figure in the Persian Church, though he was never elevated to the position of Catholics, or Patriarch. He pursued a policy of pro-Persian, anti-Roman interaction, and under his leadership the church adopted a more Nestorian theology, though it never fully adhered to the doctrine in his lifetime. He headed Synod of Beth Lapat in 484, which led the church to adopt some Nestorian teachings, and succeeded in getting the church to recognize Theodore of Mopsuestia, the mentor of Nestorius, as a spiritual authority in 486, setting the stage for future developments.
In 485 Barsauma's political enemies consecrated the moderate churchman Acacius patriarch, in the hope that he would prevent the takeover of the Church of the East by the Nestorians, but Acacius, despite frequent quarrels with Barsauma, was unable to prevent the victory of the powerful Nestorian faction. A synod held at Beth Edrai under the presidency of Acacius in 485 entrenched Nestorianism within the Church of the East.
- Wigram, W. A. (2004). An introduction to the history of the Assyrian Church, or, The Church of the Sassanid Persian Empire, 100–640 A.D. Gorgias Press. ISBN 1-59333-103-7.