In June, Austria broke the Gastein Treaty, Prussia responded by occupying Holstein, Bismarck presented a fuller version of his proposal to reform the Federal Constitution, Austria called on members of the Confederation to mobilise their armies, Prussia declared the end of the German Confederation and her troops advanced.
Within 7 weeks, the Austrian army was defeated at Koniggratz. [200,000 Prussian troops vs 180,000 Austrians] Bismarck (in tears) presented the King with an ultimatum- either war should end or he would resign. Finally, a peace settlement was agreed at Prague in August. No Austrian land was annexed by Prussia.