The Schleswig-Holstein Question (German: Schleswig-Holsteinische Frage; Danish: Spørgsmålet om Sønderjylland og Holsten) was a complex set of diplomatic and other issues arising in the 19th century from the relations of two duchies, Schleswig (Danish: Sønderjylland/Slesvig) and Holstein (Danish: Holsten), to the Danish crown and to the German Confederation.