Born in a Zoroastrian family of Persian origin in Hala, Mesopotamia. Mar Aba was secretary to the governor of Beth Garmai province before he converted to Christianity. He was baptised in Ḥīrtā and studied at the School of Nisibis. He then went to Edessa in the Roman Empire, where he learned Greek from Thomas, who became his travelling companion. He traveled widely in the Roman Empire, visiting the Holy Land, Constantinople and Egypt. He was in Constantinople sometime between 525 and 533. Because he favoured the Biblical interpretation and commentaries of Theodore of Mopsuestia, the Byzantine emperorJustinian I attempted to meet with him to persuade him to denounce Theodore's teachings. Justinian was preparing to anathematize Theodore and his works. In Alexandria, one of his pupils was the merchant and writer known as "Cosmas Indicopleustes". In his Christian Topography, written between 548 and 550, Cosmas credits Aba with teaching him everything he knows. He says that in Greek Aba went by the name Patrikios. Upon returning to Persia, Aba became a mpaššqānā or teacher of biblical exegesis at the School of Nisibis. One of his pupils there was Cyrus of Edessa. He later taught in Seleucia-Ctesiphon, the school of which he is said to have founded. Highly regarded as a scholar, he is credited with the translation of key texts, including the works of Theodore and Nestorius, from Greek into Syriac. The translator of Nestorius' Book of Heraclides dedicated his work to Aba. Aba is also remembered as the author of original works including Biblical commentaries, homilies and synodal letters. These survive today only in quotations in other works, notably those of Ishodad of Merv. A remark in the Chronicle of Seert may suggest that Aba made a translation of the Old Testament into Syriac, but there is no other evidence of this.
Patriarch
544 Synod
Aba's tenure as catholicos followed a 15-year period of schism within the church, during which remote areas had elected their own rival bishops. Aba was able to resolve this schism, visiting the disputed areas and negotiating agreements to reunite the church. In 544, he convened a synod to ratify these agreements; the synod agreed that the metropolitans of those regions under the See of Seleucia-Ctesiphon would, in the future, elect catholicoi at formal meetings. This agreement was, however, substantially subverted in later years, not least when the Persian ruler Khosrau I influenced the selection of Joseph, Aba's successor as catholicos. The acts of the synod also documented an "orthodoxy of faith", written by Aba himself. Some of its prescriptions indicate the particularly Persian character of the church in the East, including a set of marriage rules prohibiting unions between close kin, apparently formulated in deliberate response to Zoroastrian practice. In 549, Aba established a diocese for the Hephthalite Huns.
Tensions with Persia and Rome
Tensions between the Persian and Byzantine empires ran high during Mar Aba's lifetime, and, after the outbreak of the Lazic War in 541, persecution of Christians in Persia became more common. Zoroastrians hostile to Aba as an apostate pressured Khosrau to act against him, and, as punishment for proselytizing among the Zoroastrians, Aba was placed under house arrest and eventually exiled to Adurbadagan. He was allowed to return to the See after seven years and continued as Catholicos until 552, when he died – in some accounts, as a result of torture and exposure inflicted during his imprisonment.
