1653 Imperial election electoral rights in a treaty of 1619, confirmed at the Diet of Regensburg on February 25, 1623. The revolt ignited a broader religious war across Germany, the Thirty Years' War, which would involve not only the states of the empire but also Sweden, the Dutch Republic, France, Denmark–Norway, England, Scotland, Spain and Hungary and which would kill some eight million people before its end. The Peace of Westphalia which ended the war in 1648 revived the principle of "cuius regio, eius religio" established in 1555 by the Peace of Augsburg and established the modern concept of Westphalian sovereignty. It additionally
Pomeranian War Frederick's downfall and to humiliate and destroy the Swedish queen Louisa Ulrika of Prussia, Frederick's sister. The Hats faction was also encouraged to declare war by France, whose wishes were central to the Hats' actions. Frederick's invasion of Saxony in 1756 was used as a pretext for war, being denounced by both Sweden and France as a violation of the Treaty of Westphalia of 1648, of which they were both guarantors. On March 21, 1757 the governments of France and Austria agreed a convention in which Sweden and France explained that they had to maintain Germany's freedom in line with