Saint Irenaeus, Bishop of Lyons, lived in the 2nd century and was an outstanding defender of Christian teaching against Gnosticism. He was born in Smyrna, studied Hellenic wisdom, but then converted to Christianity, becoming a disciple of Saint Polycarp, who was a disciple of Saint Apostle John the Theologian.
Saint Irenaeus was ordained by Polycarp as a presbyter and sent to Gaul to preach. In Lyon, he assisted Bishop Pothinus, who later suffered for the faith. Saint Irenaeus showed courage during the persecutions of Christians, defending them and going to Rome with a message to Bishop Eleutherius.
After the martyrdom of Saint Pothinus, Saint Irenaeus became the Bishop of Lyon. He actively worked for the benefit of the Church, converting many pagans to Christianity and opposing heretics. Saint Irenaeus wrote many works, the most famous of which is "Against Heresies," where he condemned the errors of heretics and defended the true teaching of the Church.
Saint Irenaeus emphasized the importance of the four Gospels as the foundation of Christian doctrine and refuted the ideas of heretics who claimed the existence of two gods. He taught that the Old and New Testaments form a single whole, and that God is both a judge and merciful. In his works, he also explained the significance of the Old Testament as a preparation for the New.
Saint Irenaeus suffered for the faith during the reign of Emperor Severus, was beheaded, and accepted a martyr's death, receiving a crown of glory in the Kingdom of Heaven.
