In the 14th century, Margrete Valdemarsdatter managed to become the ruler of Denmark, Sweden, Norway, Iceland, Greenland and the Northern Isles uniting all of Scandinavia into a political (if not legal) union for the first time. This union became known as the Kalmar Union, and was instrumental in containing the power of the German Hanseatic league league in the Baltic sea. The union and lasted in some form or another for over 400 years. The Kalmar Union was, in some ways, a successor to the North Sea Empire forged by Svein Forkbeard in 1013, which was composed of Denmark, Norway, and England. Svein died shortly after forging his empire, but his son, Cnut the Great, was considered the second most powerful ruler in Europe (after the Holy Roman Emperor). That Empire disintegrated after the death of Cnut’s son, Harthacnut.
– A few thoughts from your friend Saxo