Cyril was born in 315 of Christian parents and succeeded Maximus as bishop of Jerusalem in 348. He was active in the Arian controversy and was exiled more than once as a result. His pastoral zeal is especially shown in his Catecheses, in which he expounded orthodox doctrine, holy Scripture and the traditions of the faith. They are still read today, and several of the Second Readings of the Office of Readings are taken from them. He died in 386. He is held in high esteem by both the Catholics and the Orthodox, and he was declared a Doctor of the Church by the Pope in 1883.

Red is the colour of fire and of blood. Liturgically, it is used to celebrate the fire of the Holy Spirit (for instance, at Pentecost) and the blood of the martyrs.