Hearing about Cyrus, John, then a Roman officer in Edessa, came to Arabia to see him. Upon meeting, they loved one another as a brother loves a brother and remained together to live a life of asceticism.
At that time, a certain Christian woman named [Athanasia], together with her three daughters, was tortured by the persecutors in the town of Canopus. Hearing of this, Cyrus and John came to Canopus to encourage the mother and her daughters not to abandon the Faith. And truly, thanks to the counsel of these saints, [Athanasia] endured all tortures and, with her daughters, was martyred for Christ. The daughters of [Athanasia] were named: St. Theoctista, age 15; St. Theodota, age 13; and St. Eudocia, age 11. The tormentors then captured Cyrus and John, who, after imprisonment and torture were beheaded in the year 311 A.D. Numerous miracles were wrought by these martyrs, both during their lives and after their deaths. Their relics were translated to Rome during the reign of Emperor Arcadius. These saints are invoked for assistance during the Blessing of Water, in the Sacrament of Holy Unction and especially by those suffering from insomnia.
Their tomb became a renowned shrine in Egypt, and a place of universal pilgrimage. It was found in the area of the modern day resort near Alexandria named Abu Kyr. (taken from: http://goarch.org/chapel/saints_view?contentid=409)
Apolytikion in the Plagal of the Fourth Tone
Since Thou hast given us the miracles of Thy holy Martyrs as an invincible battlement, by their entreaties scatter the counsels of the heathen, O Christ our God, and strenghten the faith of Orthodox Christians, since Thou alone art good and the Friend of man.
With a great voice, O ye faithful, let us hymn the great physicians of the world, the pair beloved of Christ, the luminaries who are radiant with the beams of healing; and as we stand in their temple, we cry out: Cyrus and John, the bestowers of miracles and healers of the ailing, shine forth to the ends of the world.