In Speyer, an Imperial City in on the Rhine, following the formation of the League of Torgau, an alliance of Lutheran princes, including Philip of Hesse and John of Saxony, an Imperial Diet was opened on 25 June 1526.
Charles was unable to attend and it was hosted, in his name, by his younger brother Archduke Ferdinand I of Austria. His task was to unite the Habsburg Empire. The animosity, at that time, between the Habsburgs and the pope, and much of Christendom and the threat of the Turks wakened Charles and Ferdinand’s position and they stepped back from the anti-Lutheran Edict of Worms and for the time being allowed the establishment of separate state churches in the German states of the Holy Roman Empire, and allowed the maxim that the ruler of the territory is the ruler of religion within its bounds (cuius regio, eius religio). The edict had the effect of strengthening the growth of evangelism.