St. Cyril of Jerusalem (315-386 A.D.) was a well-educated man from Jerusalem and a scholar of Sacred Scripture. He was ordained a priest by the bishop of Jerusalem shortly after the legalization of Christianity in the Roman Empire. He was given the task of catechizing new Christians leading up to and immediately following their baptism. Later he himself became bishop of Jerusalem, and soon after his ordination a miraculous apparition of a cross appeared in the sky, visible to the whole city. Because St. Cyril defended Christ's full humanity and divinity against the Arian heresy, he was exiled from his bishopric three times in twenty years due to misunderstandings, intrigue, and politics. Saint Cyril of Jerusalem is one of the early Church Fathers and one of the most important sources for how the early Church celebrated the liturgy and sacraments during the first few decades after Christianity was legalized. For St. Cyril's work in catechesis he was named a Doctor of the Church by Pope Leo XIII in 1883. His feast day is March 18th.