Austro-Prussian War
The pretext for the conflict was found in the dispute between Prussia and Austria over the administration of Schleswig-Holstein, which the two of them had conquered from Denmark and agreed to jointly occupy at the end of the Second Schleswig War in 1864. When Austria brought the dispute before the German Diet and also decided to convene the Diet of Holstein, Prussia declared that the Gastein Convention had thereby been nullified and invaded Holstein. When the German Diet responded by voting for a partial mobilization against Prussia, Bismarck claimed that the German Confederation was ended. Crown Prince Frederick "was the only member of the Prussian Crown Council to uphold the rights of the Duke of Augustenburg and oppose the idea of a war with Austria which he described as "fratricide"". Although he supported unification and the restoration of the medieval empire, "Fritz could not accept that war was the right way to unite Germany."
Prussia
By defeating the Austrian Army at the Battle of Mollwitz on 10 April 1741, Frederick succeeded in conquering Lower Silesia (the northwestern half of Silesia). In the next year, 1742, he conquered Upper Silesia (the southeastern half). Furthermore, in the third Silesian War (usually grouped with the Seven Years' War) Frederick won a victory over Austria at the Battle of Lobositz on 1 October 1756. In spite of some impressive victories afterward, his situation became far less comfortable the following years, as he failed in his attempts to knock Austria out of the war and was gradually reduced to a desperate defensive war. However, he never gave up and on 3 November 1760 the Prussian king won another battle, the hard-fought Battle of Torgau. Despite being several times on the verge of defeat Frederick, allied with Great Britain, Hanover and Hesse-Kassel, was finally able to hold the whole of Silesia against a coalition of Saxony, Austria, France and Russia. Voltaire, a close friend of the king, once described Frederick the Great's Prussia by saying "...it was Sparta in the morning, Athens in the afternoon." From these wars onwards the Austria–Prussia rivalry dominated German politics until 1866.