structural:scholar_edition, structural:summarization, structural:reformatting, stylistic:style_transfer
Viking and Middle Ages

From the 8th to the 10th century the wider Scandinavian region was the source of Vikings. They colonised, raided, and traded in all parts of Europe. The Danish Vikings were most active in the eastern and southern British Isles and Western Europe. They settled in parts of England (known as the Danelaw) under King Sweyn Forkbeard in 1013, and in France where Danes and Norwegians were allowed to settle in what would become Normandy in exchange of allegiance to Robert I of France with Rollo as first ruler. Some Anglo-Saxon pence of this period have been found in Denmark.

Denmark was largely consolidated by the late 8th century and its rulers are consistently referred to in Frankish sources as kings (reges). Under the reign of Gudfred in 804 the Danish kingdom may have included all the lands of Jutland, Scania and the Danish islands, excluding Bornholm.

The extant Danish monarchy traces its roots back to Gorm the Old, who established his reign in the early 10th century. As attested by the Jelling stones, the Danes were Christianised around 965 by Harald Bluetooth, the son of Gorm and Thyra. It is believed that Denmark became Christian for political reasons so as not to get invaded by the Holy Roman Empire. A rising Christian power in Europe, the Holy Roman Empire was an important trading partner for the Danes. As a deterrent against this threat, Harald built six fortresses around Denmark called Trelleborg and built a further Danevirke. In the early 11th century, Canute the Great won and united Denmark, England, and Norway for almost 30 years with a Scandinavian army.

Throughout the High and Late Middle Ages, Denmark also included Skåneland (the areas of Scania, Halland, and Blekinge in present-day south Sweden) and Danish kings ruled Danish Estonia, as well as the duchies of Schleswig and Holstein. Most of the latter two now form the state of Schleswig-Holstein in northern Germany.

In 1397, Denmark entered into a personal union known as the Kalmar Union with Norway and Sweden, united under Queen Margaret I. The three countries were to be treated as equals in the union. However, even from the start, Margaret may not have been so idealistic—treating Denmark as the clear "senior" partner of the union. Thus, much of the next 125 years of Scandinavian history revolves around this union, with Sweden breaking off and being re-conquered repeatedly. The issue was for practical purposes resolved on 17 June 1523, as Swedish King Gustav Vasa conquered the city of Stockholm. The Protestant Reformation spread to Scandinavia in the 1530s, and following the Count's Feud civil war, Denmark converted to Lutheranism in 1536. Later that year, Denmark entered into a union with Norway.