Augsburger Reichs- und Religionsfrieden
On 10 April 1525 Albert resigned his position, became a protestant, and in the Prussian Homage was granted the title "Duke of Prussia" by his uncle, King Sigismund I of Poland. In a deal partly brokered by Luther, Ducal Prussia became the first Protestant state, anticipating the dispensations of the Peace of Augsburg of 1555.