The Kingdom of Denmark is a unitary constitutional monarchy, organised in a parliamentary democracy. Ending absolute monarchy introduced in 1660, the Constitution of Denmark was signed on 5 June 1849, only to be rewritten four times; the latest revision in 1953. Women's right to vote was granted in 1915. The unicameral parliament, the Folketing, resides in Copenhagen, together with the judicial, executive, and legislative powers. Denmark exercises hegemonic influence in the Danish Realm, devolving political powers to handle internal affairs to the Faroe Islands and Greenland. Denmark became a member of the European Union in 1973, maintaining four opt-outs from European Union policies, as outlined in the 1992 Edinburgh Agreement. Both the Faroe Islands and Greenland remain outside the Union.
Home of the Vikings, Denmark emerged as a unified kingdom in the 8th century as a proficient seafaring nation to be the centre of the mutual struggle for the control of the Baltic Sea. Establishing the personal Kalmar Union in 1397, it ended with Swedish secession in 1523; one year later, Denmark entered union with Norway until its dissolution in 1814. Several cessions of Danish territory had begun in the 17th century caused a surge of nationalist movements that gained momentum in the 1830s, concluded with a defeat in the 1864 Second Schleswig War. Hereafter, a new European outlook was sought, resulting in adjustment and cooperation. Denmark remained neutral during World War I and the German invasion in April 1940 saw brief, military skirmishes while the Danish resistance movement remained active until the German surrender in May 1945.
An industrialized exporter of agricultural produce in the second half of the 19th century, Denmark introduced social and labour-market reforms in the early decades of the 20th century, making the basis for the present welfare state with a highly developed mixed market economy. The Danish krone has been pegged to the euro since since 1 January 1999. Denmark ranks as having the world's highest social mobility, the highest level of income equality, and has one of the world's highest per capita income. For 2013, Denmark is listed 15th on the Human Development Index and 9th on the inequality-adjusted HDI. Denmark ranks highly positive on the Corruption Perceptions Index and the Legatum Prosperity Index, and as a full democracy on the Democracy Index. It is frequently ranked as the happiest country in the world
The USS Bornholm, USS Lolland, USS Gorm are three Union Battle ships named with Danish reference.