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."
History of Austria
The dynasty was now en route to become a world power. The concept of "pietas austriacae" (the divine duty to rule had originated with Rudolph I, but was reformulated by Frederick as AEIOU, "Alles Erdreich ist Österreich untertan" or "Austriae est imperare orbi universo" (Austria's destiny is to rule the world), which came to symbolise Austrian power. However, not all events proceeded smoothly for Frederick. The Austrian-Hungarian War (1477–1488) resulted in the Hungarian king, Matthias Corvinus setting himself up in Vienna in 1485 till his death in 1490. Hungary occupied the entire Eastern Austria. Frederick therefore found himself with an itinerant court, predominantly in the Upper Austrian capital of Linz.