Tserclaes, Count of Tilly put in supreme command of imperial forces, which were shrunk despite the Swedish threat. The debate on Mantua forced Ferdinand into a peace treaty which France soon broke. The Electors blocked Ferdinand the Younger's election as King of the Romans and in the name of their own freedom revoked the Edict of Restitution. The Diet thus saw Ferdinand - previously at the height of his power - suffer his first defeat by the Imperial States, a defeat that was near-complete. Notes References (extract) Attribution Further reading Gerhard Taddey: Regensburger Kurfürstentag. In: Ders.: Lexikon der deutschen Geschichte. 2.überarb. Aufl. Stuttgart, 1982 S.1017 Johannes Burkhardt: Der Dreißigjährige Krieg. Frankfurt am Main, 1992 Regensburg Regensburg Thirty Years' War 1630 in politics Ferdinand II, Holy Roman Emperor