Cyril of Alexandria
376 — 444 · Feast day: June 27
Cyril of Alexandria was the formidable Patriarch of Alexandria from 412 to 444 and the decisive voice at the Council of Ephesus in 431, which defined Mary as Theotokos — 'God-Bearer' — and condemned the heresy of Nestorius. A relentless defender of Christ's full divinity and a controversial figure even in his own time, he is counted among the Doctors of the Church with the titles 'Pillar of Faith' and 'Seal of all the Fathers.'