The history of Norway before the age of the Vikings is indistinct from that of the rest of Scandinavia. In the 9th cent. the country was still divided among the numerous petty kings of the fylker. Harold I, of the Yngling or Scilfing dynasty (which claimed descent from one of the old Norse gods), defeated the petty kings (c.900) and conquered the Shetlands and the Orkneys, but failed to establish permanent unity. Harold's campaigns drove many nobles and their followers to settle in Iceland and France. In the next two centuries Norsemen raided widely in W Europe and established the Norse duchy of Normandy. Harold himself concentrated on developing a dynasty; before he died (c.935) the country was divided among his sons, but one of them, Haakon I, defeated (c.935) his brothers and temporarily reunited the kingdom.
Christianity, brought by English missionaries, gained a foothold under Olaf I and was established by Olaf II (reigned 1015–28). Olaf II was driven out of Norway by King Canute of England and Denmark, in league with discontented Norwegian nobles; however, his son, Magnus I, was restored (1035) to the Norwegian throne. Both Magnus and his successor, Harold III, played a vital part in the complex events then taking place in England and Denmark. After Harold died while invading England (1066), Norway entered a period of decline and civil war, precipitated by conflicting claims to the throne.
Among the major events of 12th-century Norwegian history were the mission of Nicholas Breakspear (later Pope Adrian IV), who organized the Norwegian hierarchy, and the rule of Sverre, who created a new nobility grounded in commerce and, with the help of the popular party, the Birkebeiner, consolidated the royal power. His grandson, Haakon IV, was put on the throne by the Birkebeiner in 1217; under him and under Magnus VI (reigned 1263–80) medieval Norway reached its greatest flowering and enjoyed peace and prosperity. During this time Iceland and Greenland recognized Norwegian rule.
The separate development of Norway was halted by the accession (1319) of Magnus VII, who was also king of Sweden. He was unpopular in Norway, which he was compelled to surrender (1343) to his son, Haakon VI, husband of Margaret I of Denmark. Margaret subsequently united the rule of Norway, Sweden, and Denmark in her person and in 1397 had the Kalmar Union drawn up. Although the union was strictly a personal one, Norway virtually ceased to exist as a separate kingdom and was ruled by Danish governors for the following four centuries. Its power had greatly declined even before Margaret's accession, however, and its trade had been taken over by the Hanseatic League, which maintained its chief northern office at Bergen.
Norway's political history became essentially that of Denmark. Christian III of Denmark (1535–59) introduced Lutheranism as the state religion. Under Danish rule Norway lost territory to Sweden but developed economically. The fishing industry flourished (late 17th cent.), lumbering became an important industry (18th cent.), the merchant class grew, and Norway became a naval power. During the Napoleonic Wars, Norway was blockaded by the British. In 1814, Denmark, which had sided with France, was obliged to consent to the Treaty of Kiel, by which it ceded Norway to the Swedish crown in exchange for W Pomerania.
The Norwegians resisted union with Sweden and attempted to set up a separate kingdom, with a liberal constitution and a parliament, under Prince Christian (later King Christian VIII of Denmark). A Swedish army obliged Norway to accept Charles XIII of Sweden, but the act of union of 1814 recognized Norway as an independent kingdom, in personal union with Sweden, with its own constitution and parliament. Despite some Swedish concessions to growing Norwegian nationalism, Swedish-Norwegian relations were strained throughout the 19th cent. Johan Sverdrup, the Liberal leader, succeeded in making the ministry responsible to parliament despite royal opposition (1884), but other problems remained.
The Norwegian interest in obtaining greater participation in foreign policy came to a crisis in the late 19th cent. over the issue of a separate Norwegian consular service, justified by the spectacular growth of Norwegian shipping and commercial interests. Finally, in 1905, the Storting declared the dissolution of the union and the deposition of Oscar II. Sweden acquiesced after a plebiscite showed Norwegians nearly unanimously in favor of separation; in a second vote Norway chose to become a monarchy, and parliament elected the second son of Frederick VIII of Denmark king of Norway as Haakon VII.
Two important features in Norwegian history of the late 19th and early 20th cent. were the large-scale emigration to the United States and the great arctic and antarctic explorations by such notable men as Fridtjof Nansen and Roald Amundsen. Three outstanding cultural figures of the period were Edvard Grieg, Henrik Ibsen, and Edvard Munch. In World War I, Norway remained neutral. The industrial development of Norway, spurred by the harnessing of water power, contributed to the rise of the Labor (socialist) party, which has predominated in Norwegian politics since 1927. In the 1930s much social welfare legislation was passed, including public health and housing measures, pensions, aid to the disabled, and unemployment insurance.
Norway attempted to remain neutral in World War II, but in Apr., 1940, German troops invaded, and in a short time nearly the whole country was in German hands. King Haakon and his cabinet set up a government in exile in London, and the Norwegian merchant fleet was of vital assistance to the Allies throughout the war. Despite the attempts of Vidkun Quisling to promote collaboration with the Germans, the people of Norway defied the occupation forces. German troops remained in Norway until the war ended in May, 1945. Although half of the Norwegian fleet was sunk during the war, Norway quickly recovered its commercial position. Postwar economic policy included a degree of socialism and measures such as price, interest, and dividend controls.
Norway was one of the original members of the United Nations (the Norwegian Trygve Lie was the first UN Secretary-General), and it became a member of North Atlantic Treaty Organization (NATO) in 1949. King Olaf V succeeded to the throne in 1957. Norway joined the European Free Trade Association in 1959. Norwegian voters rejected membership in the European Community (now the European Union) in 1972, but trade agreements with the market were made the next year. Between 1965 and 1971 the Labor party was out of power for the first time since 1936.
The Labor party returned to power in 1971 under the leadership of Trygve Bratteli, whose government resigned but was restored to power in the 1973 elections. Bratteli was succeeded as prime minister by Odvar Nordli in 1976, who was quickly succeeded (1977) by Gro Harlem Brundtland, Norway's first woman prime minister. Brundtland was defeated by Conservative Kåre Willoch in the 1981 election, but she returned to the office of prime minster in 1986 and 1990. In 1991, Harold V succeeded his father Olaf V as king of Norway.
Norway sparked international controversy in 1992 when it refused to conform to the International Whaling Treaty (see whaling). During 1993, the Norwegian government facilitated secret negotiations between Israel and the Palestine Liberation Organization, which led to agreements on Palestinian self-rule. Norwegian voters again rejected membership in the European Union (EU) in 1994. Bruntland resigned in 1996 and was replaced by Thorbjørn Jagland. Following elections in 1997, Jagland resigned and Christian Democrat Kjell Magne Bondevik became prime minister, heading a center-right coalition government that included the Center and Liberal parties.
In Mar., 2000, Bondevik resigned after losing a key vote in parliament, and Labor party leader Jens Stoltenberg formed a new government. In parliamentary elections in Sept., 2001, Labor suffered a significant setback, with nonsocialist opposition parties winning a bare majority of the seats. Bondevik again became prime minister, heading a center-right minority government consisting of the Christian Democrat, Conservative, and Liberal parties.
Parliamentary elections in Sept., 2005, brought Labor and its allies into office, and Stoltenberg became prime minister. The far-right Progress party, espousing a populist, anti-immigration platform, became the largest opposition party after the vote. The Labor-led coalition government remained in office after the Sept., 2009, parliamentary elections. In July, 2011, the country was stunned by the bombing of government offices in Oslo, which killed eight, and the killing of 68 people at a Labor party youth camp; the attacks were by an extreme rightist who accused the government of allowing the Islamization of Norwegian society.