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."
Seven Years' War
The Seven Years' War was a global conflict fought between 1756 and 1763. It involved every European great power of the time and spanned five continents, affecting Europe, the Americas, West Africa, India, and the Philippines. The conflict split Europe into two coalitions, led by the Kingdom of Great Britain (including the Kingdom of Prussia, the Kingdom of Portugal, the Electorate of Brunswick-Lüneburg, and other small German states) on one side and the Kingdom of France (including the Austrian-led Holy Roman Empire), the Russian Empire (until 1762), the Kingdom of Spain, and the Swedish Empire on the other. Meanwhile, in India, some regional polities within the increasingly fragmented Mughal Empire, with the support of the French, tried to crush a British attempt to conquer Bengal. The war's extent has led some historians to describe it as "World War Zero", similar in scale to other world wars.