This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Cyril of Alexandria became patriarch of Alexandria in 412 and led the fifth century campaign that made Theotokos, God bearer, the required title for Mary, against Nestorius, patriarch of Constantinople, who preferred the narrower Christotokos. The dispute was not merely verbal: which title won determined how the church would describe the relationship between Christ's divine and human natures for centuries afterward.
Cyril presided over the Council of Ephesus in 431, which condemned Nestorius before bishops sympathetic to him had arrived to take part, a piece of procedural timing that decided the council's outcome before the full body of bishops entitled to a voice in it had actually convened. That procedural haste has drawn sustained historical criticism running alongside, rather than separate from, assessment of the underlying theology Cyril was defending.
He was later declared a Doctor of the Church, an honor that sits beside rather than erases the procedural controversy of Ephesus: the theological victory and the questioned method by which it was won are both part of how Cyril's conduct at the council is remembered today.