Frontasius, Severinus, Severian, and Silanus were four missionaries who, by tradition, were sent to preach the Gospel in southern Gaul (modern France) and were martyred there for refusing to worship idols. The synaxarion places their deaths in the apostolic age, under the emperor Claudius (41-54), making them among the earliest witnesses to Christ in Gaul. They are commemorated together on June 4.
According to the tradition recorded in the Orthodox synaxarion, the four were dispatched to evangelize southern Gaul by Bishop Frontonus of Petragorium, the city now known as Périgueux. A pagan governor named Squiridonus arrested them and demanded that they renounce Christ. When they refused, he ordered that they be led outside the city, bound to pillars, and have nails driven into their heads in the manner of a crown of thorns, after which they were beheaded.
A miraculous tradition is attached to their martyrdom: the synaxarion relates that the holy martyrs, by the power of God, took up their severed heads and carried them to the church of the Mother of God where Bishop Frontonus was at prayer; there they laid their heads at the bishop's feet, signed themselves with the cross, and died. Western sources connect the four with Le Puy (Puy-en-Velay), where they are remembered as the Martyrs of Puy and where, by tradition, Bishop Fronto buried them together in the church of Notre Dame with their bodies arranged in the form of a cross.