Johannes Oecolampadius was a German Protestant reformer in the Calvinist tradition from the Electoral Palatinate. He was the leader of the Protestant faction in the Baden Disputation of 1526, and he was one of the founders of Protestant theology, engaging in disputes with Erasmus, Huldrych Zwingli, Martin Luther and Martin Bucer. Calvin adopted his view on the Eucharist dispute.

Reformed Christianity, also called Calvinism, is a major branch of Protestantism that began during the sixteenth-century Protestant Reformation, a schism in the Western Church. In the modern day, it is largely represented by the Continental, Presbyterian, and Congregational traditions, as well as parts of the Anglican and Baptist traditions.