the so-called Danish-British Gunboat War, but the British control of the waterways between Denmark and Norway proved disastrous to the union's economy and in 1813, Denmark-Norway went bankrupt. The Danish-Norwegian union was dissolved by the Treaty of Kiel in 1814. Norway entered a new union with Sweden which lasted until 1905. Denmark kept the colonies of Iceland, Faroe Islands and Greenland. Apart from the Nordic colonies, Denmark ruled over Danish India (Tranquebar in India) from 1620 to 1869, the Danish Gold Coast (Ghana) from 1658 to 1850, and the Danish West Indies (the U.S. Virgin Islands) from 1671 to 1917.
Constitutional monarchy
The Danish liberal and national movement gained momentum in the 1830s, and after the European Revolutions of 1848 Denmark peacefully became a constitutional monarchy on 5 June 1849. After the Second War of Schleswig (Danish: Slesvig) in 1864, Denmark was forced to cede Schleswig and Holstein to Prussia, in a defeat that left deep marks on the Danish national identity. After these events, Denmark pursued a policy of neutrality in Europe.
After the defeat of Germany in World War I, the Versailles powers offered to return the then-German region of Schleswig-Holstein to Denmark. Fearing German irredentism, Denmark refused to consider the return of the area and insisted on a plebiscite concerning the return of Schleswig. The two Schleswig Plebiscites took place on 10 February and 14 March, respectively. On 10 July 1920, after the plebiscite and the King's signature (9 July) on the reunion document, Northern Schleswig (Sønderjylland) was recovered by Denmark, thereby adding 163,600 inhabitants and 3,984 km². The reunion day (Genforeningsdag) is celebrated every year 15 June on Valdemarsdag.
Germany's invasion of Denmark on 9 April 1940 – code named Operation Weserübung – met only two hours of military resistance before the Danish government surrendered. Economic co-operation between
