[1] The period of colonial expansion marked a rise in the status and power of Danes and Norwegians in the Kalmar Union.

In the 17th century, following territorial losses on the Scandinavian Peninsula, Denmark–Norway began to develop forts with trading posts in West Africa, and colonies in the Caribbean, and the Indian subcontinent.

Christian IV first initiated the policy of expanding Denmark–Norway's overseas trade, as part of the mercantilist wave that was sweeping Europe.

Denmark-Norway maintained several trading stations and four forts along the Gold Coast in West Africa, especially around modern day Ghana.

Denmark maintained a scattering of small colonies and trading posts throughout the Indian sub-continent from the 17th to 19th centuries, after which most were sold or ceded to Britain which had become the dominant power there.

[3] Several Danish-American succession talks had been made since 1870 due to a rising number of riots and unrest from the poorer English-speaking population.

The Zahle Government (1914–1920) held a heavily boycotted election for Danish mainland constituencies, which produced a minority for the sale of the islands.

After the Norse settlement in Greenland finally disappeared in the 15th century, Europeans did not settle the island again until 1721, when the Lutheran minister Hans Egede arrived and established the town now known as Nuuk.

After Norway was ceded to the king of Sweden in 1814 following the Napoleonic Wars, Denmark retained the old territorial claims as a condition of the Treaty of Kiel.

The development and settlement of Greenland accelerated in 1945, instigated by the region's geostrategic importance in the Cold War era, itself exemplified and manifested by the U.S. Air Base of Thule from 1943.

Another reason and driving force was the emergence of fundamental technical abilities, such as aircraft and icebreakers at Greenland's disposition, giving the otherwise remote island a supply situation somewhat similar to Europe.