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."
Silesian Wars
Peace with Prussia allowed the Austrians and their British–Hanoverian allies to reverse the gains made by the French and Bavarians in 1741. By the summer of 1743, Austria recovered control of Bohemia, drove the French back across the Rhine into Alsace, and occupied Bavaria, exiling the Bavarian Elector Charles Albert (now crowned Holy Roman Emperor Charles VII) to Frankfurt. In September 1743, Britain, Austria and Savoy–Sardinia concluded a new alliance under the Treaty of Worms that led Frederick to suspect that Maria Theresa meant to retake Silesia as soon as the war elsewhere was concluded. So, on 7 August 1744 Prussia declared its intervention in the Austrian war on behalf of Bavarian Emperor Charles, and Frederick led soldiers across the frontier into Bohemia on 15 August 1744, beginning the Second Silesian War.