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."
Austria–Prussia rivalry
The rivalry is largely held to have begun when upon the death of the Habsburg Emperor Charles VI in 1740, King Frederick the Great of Prussia launched an invasion of Austrian-controlled Silesia, starting the First Silesian War (of three Silesian Wars to come) against Maria Theresa. Frederick had broken his promise to acknowledge the Pragmatic Sanction of 1713 and the indivisibility of the Habsburg territories, whereby he sparked off the pan–European War of the Austrian Succession. He decisively defeated the Austrian troops at the 1742 Battle of Chotusitz, whereafter Maria Theresa, by the Treaties of Breslau and Berlin, had to cede the bulk of the Silesian lands to Prussia.
At the time, Austria still claimed the mantle of the Empire and was the chief force of the disunited German states. Until 1745, Maria Theresa was able to regain the Imperial crown from her Wittelsbach rival Charles VII by occupying his Bavarian lands, but, despite her Quadruple Alliance with Great Britain, the Dutch Republic and Saxony failed to recapture Silesia: The Second Silesian War started with Frederick's invasion into Bohemia in 1744 and after the Prussian victory at the 1745 Battle of Kesselsdorf, by the Treaty of Dresden the "status quo ante bellum" was confirmed: Frederick kept Silesia but finally acknowledged the accession of Maria Theresa's husband, Emperor Francis I. The terms were again confirmed by the final Peace of Aix-la-Chapelle in 1748.