Greek-speaking Alexandrian Church Father (c. 376-444) and principal theological architect of the Council of Ephesus (431). Patriarch of Alexandria from 412, succeeding his uncle Theophilus (the patriarch who had orchestrated John Chrysostom's deposition); served as patriarch until his death in 444 (thirty-two years). Cyril's principal historical-theological significance is his leadership of the orthodox party against Nestorius of Constantinople (patriarch from 428). Nestorius had objected to the title Theotokos (God-bearer) applied to Mary, preferring the title Christotokos (Christ-bearer) on the grounds that Theotokos conflated the divine and human natures of Christ. Cyril vigorously responded that the title Theotokos was orthodox precisely because the one Person born of Mary was the eternal Son of God in His incarnate state — one Person with two natures (divine and human), the natures unmixed but the Person unified, such that the title Theotokos properly applied to Mary as the mother of the incarnate Son. The Cyrilline-Nestorian controversy was settled at the Council of Ephesus (431), which condemned Nestorius, affirmed the title Theotokos, and articulated the orthodox Christological position that prepared for the later more comprehensive Definition of Chalcedon (451, two years after Cyril's death). Cyril's principal works include the Commentary on John, the Commentary on Luke, the Glaphyra (allegorical commentaries on the Pentateuch), the Thesaurus de Sancta et Consubstantiali Trinitate, and the polemical writings against Nestorius. The patriarchal-Reformed reader recognizes Cyril as the substantive Christological theologian of the early fifth century, whose work at Ephesus prepared for the comprehensive Chalcedonian Christology that the Reformed-confessional tradition fully receives.