Danish-German War
The Danish-German War, also known as the Second Schleswig War, took place from 1864 to 1865. It was fought between the Kingdom of Denmark and the German Confederation, primarily led by Prussia and Austria. The conflict arose over the control of the duchies of Schleswig and Holstein, which had significant German populations but were ruled by Denmark.
The war ended with a decisive victory for the German forces, leading to the Treaty of Vienna in 1864. As a result, Denmark ceded both duchies to Prussia and Austria, significantly altering the balance of power in Northern Europe and setting the stage for future conflicts, including the Franco-Prussian War.