High Quality Content by WIKIPEDIA articles! The Schleswig-Holstein Question refers to a complex of diplomatic and other issues arising in the 19th century from the relations of two duchies, Schleswig and Holstein, to the Danish crown and to the German Confederation. Schleswig was a part of Denmark during the Viking Age, and became a Danish duchy in the 12th century. Denmark repeatedly tried to integrate the Duchy of Schleswig into the Danish kingdom. In March 27, 1848 Frederick VII of Denmark announced to the people of Schleswig the promulgation of a liberal constitution under which the duchy, while preserving its local autonomy, would become an integral part of Denmark.