Irenaeus of Lyons (ca. 130–ca. 202) is considered the founder of patristic biblical theology. His works include Against Heresies and Demonstration of the Apostolic Preaching. An acquaintance of St. Polycarp and successor to a martyred bishop of Lyons, Irenaeus is also believed to have been martyred in 202. For centuries, he has been venerated as a saint by churches of the East and West.