Karlstadt (both: kärl`shtät), or
Karolostadt (kä`rôlōshtät'), c.1480–1541, German Protestant reformer, whose original name was Andreas Rudolph Bodenstein. As early as 1516, Carlstadt presented theses denying free will and asserting the doctrine of salvation by grace alone. In 1518 he supported Luther against the attacks of Johann Maier von Eck by maintaining the supremacy of Scripture and in 1519 he appeared with Luther against Eck in the public disputation at Leipzig. He soon became known as the most extreme of the Wittenberg reformers. During Luther's stay at the Wartburg (1521–22) he became the leader at Wittenberg and began to put his radical beliefs into effect. His extreme spiritualization of religion tended to undermine the importance of the church and the sacraments. Upon his return Luther accused Carlstadt of betrayal and restored the more orthodox practices. Accused of revolutionary political activity he fled to Switzerland where he was protected by the Zürich preachers and became professor of theology at Basel.