Real unions

Denmark–Norway was a 16th-to-19th-century multi-national and multi-lingual real union consisting of the Kingdom of Denmark, the Kingdom of Norway (including the then Norwegian overseas possessions: the Faroe Islands, Iceland, Greenland, and other possessions), the Duchy of Schleswig, and the Duchy of Holstein. The state also claimed sovereignty over three historical peoples: Frisians, Gutes and Wends. Denmark–Norway had several colonies, namely the Danish Gold Coast, Danish India (the Nicobar Islands, Serampore, Tharangambadi), and the Danish West Indies.

1569 union of Poland and Lithuania

Italian possession in East Africa between 1936 and 1941

constitutional reform that established the dual monarchy of Austria-Hungary

collective name for the duchies of Saxe-Coburg and Saxe-Gotha in Germany

form of government

former territories in modern Germany and the Netherlands

state of the Empire (1623–1811)