Map of the territorial changes due to the Treaty of Vienna.
The Treaty of Vienna (Danish: Freden i Wien; German: Frieden von Wien) was a peace treaty signed on 30 October 1864 in Vienna between the Austrian Empire, the Kingdom of Prussia, and the Kingdom of Denmark. The treaty ended the Second War of Schleswig. Based on the terms of the treaty, Prussia would administer Schleswig and Austria would administer Holstein. Disputes over the administration of the two provinces would lead to the Austro-Prussian War.