Johannes Bugenhagen, also called Doctor Pomeranus by Martin Luther, was a German theologian and Lutheran priest who introduced the Protestant Reformation in the Duchy of Pomerania and Denmark in the 16th century. Contributions of Karlstadt and Luther to the translation of theology into social legislation were most fully realized by Bugenhagen. Among his major accomplishments was organization of Lutheran churches in Northern Germany and Scandinavia. He has also been called the "Second Apostle of the North".