Cyril succeeded his uncle in the See of Alexandria in 412. Nestorius, his counterpart in Constantinople, was preaching sermons in which he called Mary the “Christ-bearer” rather than the traditional title “God-bearer” (Theotokos). Cyril responded to Nestorius by explaining the danger of the term “Christ-bearer”: it divided the human and the divine in the person of Christ, threatening the meaning of the Incarnation, God-become-man. Cyril’s assessment was confirmed at the Council of Ephesus in 431. Revered in the East as the “guardian of exactitude,” Cyril was declared a Doctor of the Church by Pope Leo XIII in 1882 (credit Magnificat.net). For more about this great saint, and for an excerpt of one of his writings of Orthodox teaching, please click on the image. Peace be with you!