Irenaeus

St. Irenaeus (c. 130-202 AD) was a prominent early Christian theologian and bishop of Lyon in ancient Gaul (modern-day France). Born in Smyrna (modern-day Turkey), he studied under St. Polycarp, a disciple of the Apostle John. Irenaeus is renowned for his extensive writings defending Christian orthodoxy against Gnostic heresies. As bishop of Lyon, he worked to unify the Church and supported the Roman date for the celebration of Easter. He was martyred during the persecution of Christians under Roman Emperor Septimius Severus. Irenaeus is venerated as a Doctor of the Church for his theological contributions and is the patron saint of theological clarification.