Cyril Of Alexandria, a Christian saint, patriarch, and doctor, born in Alexandria about 376, died there in 444. The patriarch Theo-philus, his uncle, had him educated under the abbot Serapion in one of the numerous monasteries which then flourished around the Natron lakes (Nitrice), in the delta of the Nile. At the end of his course of studies he was ordained priest and appointed preacher in the cathedral, where his discourses gained him great popularity. In 403 he accompanied Theophilus to the famous " synod of the oak" in Chalcedon, which sentenced St. John Chrysostom to deposition and banishment. This involved both himself and Theophilus in the excommunication pronounced by the pope on the persecutors of Chrysostom. Theophilus died Oct. 15, 412; and three days later, after a violent contest, Cyril was elected bishop of Alexandria. He commenced his official career by silencing the Novatians, whose churches he closed. According to the historian Socrates, who is accused of being favorable to the Novatians, and others, this step was followed by the forcible expulsion of the Jews, numbering 40,000, from Alexandria, and by a bitter quarrel between the patriarch and Orestes, prefect of Egypt. The prefect denounced the act of Cyril as a usurpation of the civil authority, alike opposed to law and good policy; but Cyril managed to explain his conduct to the satisfaction of the emperor.

As Orestes repelled every advance toward a reconciliation, the popular excitement increased, the opinion having gone abroad that the prefect opposed the bishop while he favored Jews, heretics, and pagans. Thereupon 500 monks from the Natron lakes, having flocked into Alexandria to the bishop's support, met the prefect in the streets, attacked and dispersed his escort, and demolished his chariot, while their leader, Am-monius, wounded Orestes in the face. The arrest, sentence, and execution of Ammonius only brought the mischief to a crisis. Orestes, as well as the celebrated Synesius, bishop of Cyrene, was wont to attend the lessons of llypatia. The rumor having spread that this accomplished woman, who was a pagan, was the chief instigator of the prefect's opposition, she was waylaid on her return from the schools, dragged from her chariot, borne off to a neighboring church, and murdered. In 420 Atticus, bishop of Antioch, wrote to Cyril, urging him to do justice to the memory of Chrysostom by replacing his name on the dyptichs.

Cyril's reply is full of unrelenting animosity; but in 421 he yielded the point, and thus at length became reconciled with the church of Rome. In the stormy controversy about the Nestorian heresy, commenced in 428, Cyril bore such a prominent part on the orthodox. side that he is still called in the schools "the doctor of the Incarnation." The fact of Nestorius having been a monk in Antioch, and his great reputation for ascetic virtue, obtained many adherents to his doctrine even in the monasteries of Egypt. Cyril took the alarm, warned both the monks and his people against the new doctrine, and wrote to Nestorius himself, who made a haughty reply. In February, 430, Cyril convened a synod in Alexandria, in which a formal expostulation was drawn up, and sent with a synodal letter to Nestorius. This proving of no avail, a second synod assembled in June, in which an exposition of the Nestorian doctrines was drawn up and sent to Rome. This appeal to the pope produced intense irritation in Constantinople, which was increased by letters, or rather doctrinal treatises, addressed by Cyril to the emperor, to his sister Pulcheria, and to the chief personages of the empire.

The church of Antioch and the whole of Syria took up the cause of Nestorius, thinking that Cyril and the bishops of his province leaned to the heresy of the Apollinarists; and so this misunderstanding was complicated by national animosities. Pope Celestine I., in August, 430, condemned in council the doctrine of Nestorius, and gave Cyril full power to demand a retraction from him, and to name his successor in case he should prove refractory. On receipt of the pope's decision, Cyril called his suffragans together in the following November, and framed his "twelve anathematisms," embodying the twelve most obnoxious propositions from the writings of Nestorius. These, with the pope's letter and sentence, were borne to Constantinople by a deputation of bishops, and only drew from Nestorius twelve counter-anathemas. John of Antioch and the bishops of Syria wrote to Nestorius, advising him to yield to the pope's decree and retract; but he was deaf to their prayers and those of the emperor. The only remedy was now thought to be a general council, which assembled in Ephesus in June, 431, and after vainly summoning Nestorius to appear, condemned his doctrine by the adoption of Cyril's "anathematisms," and sentenced him to be deposed.

Shortly after John of Antioch arrived, and at the head of 30 bishops held a second council, which condemned as illegal the proceedings of the 200 bishops under Cyril, excommunicated them all, and sentenced the patriarch of Alexandria and the bishop of Ephesus to be deposed. The emperor, misinformed about the respective numbers and acts of the two bodies, caused Nestorius, Cyril, and Memnon of Ephesus to be imprisoned, in hope of thus obtaining peace. Soon after, however, the sentence against Nestorius was carried into effect, and Cyril and Memnon were set at liberty. Cyril returned to Alexandria, where for the next few years he labored to perfect the pacification of the church, which, commenced at Ephesus, was consummated in the first months of 433, by the submission of John of Antioch and the Syrian bishops. This fact Cyril announced to his people, April 23 of that year. His feast is celebrated by the Greeks on Jan. 18, and by the Latins on Jan. 28. - The best edition of Cyril's works, exegetical, doctrinal, and controversial, is that by Jean Aubert (7 vols, folio, Paris, 1638), reprinted by Migne in his Patrologie grecque (vols, lxviii. to lxxvii., Paris, 1857-'66). Besides this, there is the Cologne folio (2 vols., 1546), and another Paris edition (2 vols, fol., 1692), containing the Greek text with notes.