Luther's new theology, and the social and political doctrines he derived from it, soon became officially accepted throughout a wide area of northern Europe. The earliest moves were made in Germany, where the Elector Frederick the Wise of Saxony effectively led the way when he granted protection to Luther after his excommunication in 1520 (Fife, 1957, pp. 586–91). Five years later, when Frederick was succeeded by his son the Elector John, Saxony became a Lutheran principality. The same year saw the acceptance of Lutheranism by Albert of Hohenzollern in the Duchy of Prussia, and in the following year the young Landgrave Philip of Hesse held a synod at Homberg at which he imposed a Lutheran Church ordinance throughout his territories. By 1528 the list of German princes who had left the Catholic Church included the Dukes of Brunswick and Schleswig, the Count of Mansfeld and the Margrave of Brandenburg-Ansbach; by 1534 they had been joined by the rulers of Nassau, Pomerania and Württemberg. Meanwhile a number of a Imperial cities had become converted. By 1525 the Lutherans had gained control in Altenburg, Bremen, Erfurt, Gotha, Magdeburg and Nuremberg; by 1534 they had been joined by Augsburg, Frankfurt, Hanover, Strasbourg and Ulm.

Scandinavia was the next region to adopt the new faith. The Reformation first took effective root in Denmark, after the Duke of Schleswig Holstein succeeded the exiled Christian II as King Frederick I in 1523.