In 1863–64, disputes between Prussia and Denmark over Schleswig escalated, which was not part of the German Confederation, and which Danish nationalists wanted to incorporate into the Danish kingdom. The conflict led to the Second War of Schleswig in 1864. Prussia, joined by Austria, easily defeated Denmark and occupied Jutland. The Danes were forced to cede both the Duchy of Schleswig and the Duchy of Holstein to Austria and Prussia. The subsequent management of the two duchies led to tensions between Austria and Prussia. Austria wanted the duchies to become an independent entity within the German Confederation, while Prussia intended to annex them. The disagreement served as a pretext for the Seven Weeks War between Austria and Prussia, that broke out in June 1866. In July, the two armies clashed at Sadowa-Königgrätz (Bohemia) in an enormous battle involving half a million men. Prussian superior logistics and the modern breech-loading needle guns superiority over the slow muzzle-loading rifles of the Austrians, proved to be elementary for Prussia's victory. The battle had also decided the struggle for hegemony in Germany and Bismarck was deliberately lenient with defeated Austria, that was to play only a subordinate role in future German affairs.