There is much about Cyril's life which still remains unclear, and even during his lifetime he was regarded with doubt and suspicion. He was born about 315 in Jerusalem or its environs, and it not precisely known when he entered the clergy. By 348 he a deacon and in that year during Lent and on Holy Saturday delivered his famous Catechetical Lectures (divided into the introductory Procatechesis; eighteen Catecheses; and five Mystagogical Catecheses). Sometime between 348 and 351 he be me bishop of Jerusalem. Cyril's elevation was questioned by Jerome and Rufinus, and it has long been the subject of controversy because he was probably consecrated by Acacius of Caesarea and Patrophilus of Scythopolis; that is, by prelates whose orthodoxy was doubtful. In a letter addressed to Pope Damasus Cyril had to prove to the fathers at the council of Constantinople in 382 that his installation was legal and according to canon law (Theodoret, Historia ecclesiastica 5.9).
About 355 Cyril and Acacius quarreled over the precedence and jurisdiction of their respective metropolitanates. They probably disagreed on dogmatic matters as well. Cyril was deposed, and under pressure he withdrew first to Antioch and then to Tarsus. There he became a supporter of the homoiousians and sat with them at the council of Seleucia in 359. The council reinstated him as bishop of Jerusalem, but in the next year he was exiled again and returned only during the reign of Julian in 362. In 367 under Valens he was again forced to leave Jerusalem until 378, and nothing is known of his life during this period. In 381 Cyril participated at the Second Ecumenical Council. He died in 387. These few facts are all that is definitely known about his life.
The difference of opinion regarding Cyril is understandable in of the religious controversies which raged during his life . Cyril supported the anti-Nicene movement, first as a "Eusebian" and then as a "homoiousian," and this would be enough make his orthodoxy questionable. He sided with Meletius in Antioch, which explains why Jerome regarded him with such extreme suspicion. However, the testimony of the fathers at the Council of 382 dispels all doubt: "At various times he greatly struggled against Arianism." Theodoret later refers to him as a "defender of the apostolic faith."


