Johann Maier von Eck, often anglicized as John Eck, was a German Catholic theologian, scholastic, prelate, and a pioneer of the counter-reformation who was among Martin Luther's most important interlocutors and theological opponents.

Martin Luther was a German priest, theologian, author, hymnwriter, professor, and Augustinian friar. Luther was the seminal figure of the Protestant Reformation, and his theological beliefs form the basis of Lutheranism. He is regarded as one of the most influential figures in Western and Christian history.