The Schleswig-Holstein War, also known as the Second Schleswig War or the Danish-German War of 1864, was a conflict between Denmark and the German Confederation. The war was primarily fought over the duchies of Schleswig and Holstein, which had a mixed Danish and German population. The war began in 1864 when Denmark attempted to integrate the duchies into the Danish Kingdom, a move opposed by the German Confederation. Prussia and Austria, leading members of the Confederation, intervened on behal