In Prehistoric times, Norway was originally inhabited by pre-Indo-European Hunter-gatherer cultures. Toward the end of the 3rd millennium BC these were overrun by Proto-Indo-European speaking Battle-Axe peoples, an individualistic and patriarchal culture who shared resemblances with the Siberian Afanasevo culture. These people, who are believed to be the earliest ancestors of modern Norwegians, brought domesticated horses, agriculture, cattle and wheel technology to the region. During the Nordic Bronze Age, an advanced Proto-Norse speaking civilization engaged in maritime trade and manufacturing of bronze weapons and gold jewellery emerged in coastal Norway. It has been assumed that this civilization was founded in amber trade, through contacts with Central European and Mediterranean cultures. Following the Pre-Roman Iron Age and the Barbarian invasions, Harald I of Norway unified the Norse petty kingdoms under one Norwegian King, after being victorious at the The Battle of Hafrsfjord in the Viking age 880s. Two centuries of Viking raids into Europe, and colonization of Iceland, Greenland, North America, Britain and Eastern Europe tapered off following the decline of Norse paganism with the the adoption of Christianity by King Olav Tryggvason in 994, and the subsequent battle of Stiklestad in 1030. During The Black Death, approximately 60% of the population died, resulting in a period of social and economic decline for the already sparsely populated Kingdom. Thus, in 1397, Norway was absorbed into a union with Denmark. Under influence from the Danes and the Hanseatic league, the Norwegian West Norse language gradually became extinct. In 1814, following Denmark-Norway's defeat in the Napoleonic Wars, the Norwegians resisted the cession of their country to Sweden and adopted a new constitution. Sweden then invaded Norway but agreed to let Norway keep its constitution in return for accepting the union under a Swedish king. Rising nationalism throughout the 19th century led to a 1905 referendum granting Norway independence. Discovery of oil and gas in adjacent waters in the late 1960s boosted Norway's economic fortunes. In referenda held in 1972 and 1994, Norway rejected joining the EU. Key domestic issues include immigration and integration of ethnic minorities, maintaining the country's extensive social safety net with an aging population, and preserving economic competitiveness.
Norway is a unitary parliamentary democracy and constitutional monarchy, with King Harald V as its head of state and Jens Stoltenberg as its prime minister. It is a unitary state with administrative subdivisions on two levels known as counties (fylker) and municipalities (kommuner). The Sámi people have a certain amount of self-determination and influence over traditional territories through the Sámi Parliament and the Finnmark Act. Although having rejected European Union membership in two referenda, Norway maintains close ties with the union and its member countries, as well as with the United States. Norway remains one of the biggest financial contributors to the United Nations, and participates with UN forces in international missions, notably in Afghanistan, Kosovo, and Sudan. Norway is a founding member of the United Nations, NATO, the Council of Europe, and the Nordic Council, and is a member of the European Economic Area, the WTO, and the OECD.
Norway has extensive reserves of petroleum, natural gas, minerals, forests, seafood, fresh water, and hydropower. It is the world's largest producer of oil and natural gas per capita outside of the Middle East, and the petroleum industry accounts for around a quarter of the Gross domestic product. The country maintains a Scandinavian welfare model with universal health-care, subsidized higher education, and a comprehensive social security system. From 2001 to 2007,and then again in 2009 and 2010, Norway had the highest human development in the world.