Gérald Gambier via Wikimedia (Public Domain).
A stained-glass window by Lucien Bégule depicting St. Irenaeus at the Church of St, Irenaeus in Lyon, France.

St. Irenaeus was a second-century bishop and writer revered by both Catholics and Orthodox Christians and known for refuting the heresies of Gnosticism with a defense of both Christ’s humanity and divinity.