Bp. of Constantinople from 428 to 431. Syriac sources put his birthplace in Germanicea (modern Kahramanmaraş) in the province of Euphratesia, although these sources may misunderstand the statement of the church historian Socrates, a contemporary of Nestorius, that his family came from that town (Ecclesiastical History, 7.29). There is no evidence that Nestorius could speak or write Syriac, despite his family background. In Antioch he distinguished himself as an orator and perhaps planned a legal career before being drawn to the vibrant monastic life of the city. Although it is not clear that Nestorius studied under Theodore of Mopsuestia directly, his subsequent insistence on the two natures firmly placed him within Theodore’s intellectual milieu.

When Sisinnius of Constantinople died on 24 Dec. 427, several candidates vied for his position, including Philip, future bp. of Side, and Proclus of Cyzicus. According to Nestorius himself, the emperor Theodosius personally intervened to have him brought to the capital as an outsider to cut through the acrimonious dispute between the factions. Ordained bp. on 10 April 428, Nestorius vigorously pursued pagans and heretics and likely induced the emperor to issue a new edict against a whole host of aberrant beliefs (Codex Theodosianus 16.5.66; 20 May 428). He likely also celebrated the first liturgical commemoration for his fellow Antiochene and past bp. of Constantinople, John Chrysostom, on 26 Sept. 428.

Perhaps as early as the summer 428 members of Nestorius’s cadre in the capital, the presbyter Anastasius and Dorotheus of Marcianopolis, made denunciations of the appellation Theotokos (lit. ‘God-bearer’) for the Virgin Mary. By the winter of 428/9 sermons to this effect, some of which were almost surely by Nestorius, began circulating among the monasteries of Egypt. These soon elicited a critical reaction from Cyril of Alexandria, who addressed three letters to Nestorius, as well as others to Celestine of Rome in order to gain the pope’s support. Nestorius, however, refused to distance himself from the beliefs of his subordinates and continued to quibble with the legitimacy of Theotokos, and proposed instead a neologism, Christotokos (‘Christ-bearer’) as a compromise. In order to put to rest the growing controversy, the emperor summoned a council to meet at Ephesus in 431 to discuss the faith.

Nestorius refrained from attending not only Cyril’s council, which deposed him, but also, it seems, the counter-council convened by John of Antioch to fight his case. Instead he asked the emperor repeatedly to permit his retirement from the episcopate and his return to his monastery in Antioch, a request to which the emperor finally acquiesced in the late summer of 431. Nestorius lived just outside of Antioch until an imperial order of 435 exiled him to Petra. He was transferred later to the Oasis in Egypt, where, according to excerpts of his letters preserved in Evagrius Scholasticus (Ecclesiastical History, 1.7) he was captured by raiding tribes, and moved from Panopolis in the Thebaid to Elephantine, 320 km. to the south, and then back to Panopolis where he remained until his death late in the year 450.