Occasion:
Austria supported Schleswig Holstein in their struggle for independence against Prussia after the conclusion of the Danish War. An attempted congress of neutrals failed. Austria called on the Diet of Frankfort to take the affairs of Schleswig Holstein into its own hands, and demanded and obtained the mobilization of the whole Federal armies. Prussia declared that this action made an end of the Federal Union, and submitted a new plan for the organization of Germany, which was refused. Diplomatic relations were broken off June 12, 1866.