The Viking Age (800-1050 AD) was a period of Scandinavian expansion through trade, colonization and raids.
The first raid was against Lindisfarne (England) in 793 and is considered the beginning of the Viking Age. This could
take place because of the development of the longship, suitable for travel across the sea, and advanced navigation
techniques. Vikings were well-equipped, had chain mail armor, were well-trained and had a psychological advantage over
Christian counterparts since they believed that being killed in combat would result in them going to Valhalla. In
addition to gold and silver, an important outcome from the raids were thralls (unfree servant), which were
brought to the Norwegian farms as slave workforce. While the men were out at sea, the management of the farm was under
control of the women.
The 13th century is described as Norway's Golden Age, with peace and increase in trade, especially with the
British Islands, although Germany became increasingly important towards the end of the century. Throughout the High
Middle Ages the king established Norway as a state with a central administration with local representatives. In 1349
the Black Death spread to Norway and had within a year killed a third of the population. Many communities were entire
wiped out, resulting in an abundance of land, allowing farmers to switch to more animal husbandry. The reduction in
taxes weakened the king's position, and many aristocrats lost the basis for their surplus, reducing some to mere
farmers.
In 1397, under Margaret I, the Kalmar Union (1397-1536) was created between the three Scandinavian
countries. Margaret pursued a centralising policy which inevitably favoured Denmark, because it had a greater
population than Norway and Sweden combined. Margaret also granted trade privileges to the Hanseatic merchants of Lübeck
in Bergen in return for recognition of her right to rule, and these hurt the Norwegian economy. The Hanseatic merchants
formed a state within a state in Bergen for generations.
Sweden was able to pull out of the Kalmar Union in 1523, thus creating Denmark–Norway (1536-1814) under the rule
of a king in Copenhagen. Frederick I of Denmark favoured Martin Luther's Reformation, but it was not popular in Norway,
where the Church was the one national institution and the country was too poor for the clergy to be very corrupt.
Initially, Frederick agreed not to try to introduce Protestantism to Norway but in 1529 he changed his mind. All church
valuables were sent to Copenhagen and the forty percent of the land which was owned by the church came under the control
of the king. Danish was introduced as a written language, although Norwegian remained distinct dialects. Professional
administration was now needed and power shifted from the provincial nobility to the royal administration: district
stipendiary magistrates were appointed as judges and the sheriffs became employees of the crown rather than of the
local nobility. In 1572 a governor-general was appointed for Norway with a seat at Akershus Fortress in Oslo. From
the 1620s professional military officers were employed.
After Denmark–Norway was attacked by the United Kingdom at the Battle of Copenhagen (1807), it entered into an alliance
with Napoleon. As the Danish kingdom found itself on the losing side in 1814, it was forced, under terms of the
"Treaty of Kiel", to cede Norway to the king of Sweden, while the old Norwegian provinces of Iceland, Greenland
and the Faroe Islands remained with the Danish crown. The Union between Sweden and Norway (1814 - 1905) was
born.
Christian Michelsen, a shipping magnate and statesman, Prime Minister of Norway from 1905 to 1907, played a
central role in the peaceful separation of Norway from Sweden on 7 June 1905. After a national referendum confirmed
the people's preference for a monarchy over a republic, the Norwegian government offered the throne of Norway to
Prince Carl of Denmark, and Parliament unanimously elected him king. He took the name of Haakon VII, after
the mediæval kings of independent Norway.