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."
Wars and battles involving Prussia
The Seven Years' War, fought between Prussia and Great Britain on one side and Austria, France, Sweden(1757–62) and Russia on the other, involved all the great European powers of the time. In the Third Silesian War (the Austrian-Prussian theatre), Austria's goal was the reconquest of Silesia, but Frederick II pre-empted his enemies, and on 29 August 1756 crossed the border of Saxony without a prior declaration of war. Military success alternated and the Prussian army faced defeat in the end, in spite of major victories. On 15 February 1763 the Peace of Hubertusburg was signed between Prussia and its opponents. The status quo ante was restored. The war established Prussia as the fifth major power in Europe, but Prussia lost 180,000 soldiers during the war.