From the demise of the Roman Empire to the triumph of William the Conqueror in 1066 CE, the British Isles were the scene of repeated looting and invasion from the Scandinavians. In fact, the English, or Anglo-Saxons, were themselves invaders who had arrived in the fifth century from parts of Saxony, Frisia and Jutland, and seized control over the crumbling remains of post-Roman Britain. The greatest of these invaders were Swen Forkbeard and his son Cnut the Great, who ruled until 1035 CE and was simultaneously king of Denmark, England and Norway, known as the Anglo-Scandinavian or North Sea Empire:

From the demise of the Roman Empire to the triumph of William the Conqueror in 1066 CE, the British Isles were the scene of repeated looting and invasion from the Scandinavians. In fact, the English, or Anglo-Saxons, were themselves invaders who had arrived in the fifth century from parts of Saxony, Frisia and Jutland, and seized control over the crumbling remains of post-Roman Britain. The greatest of these invaders were Swen Forkbeard and his son Cnut the Great, who ruled until 1035 CE and was simultaneously king of Denmark, England and Norway, known as the Anglo-Scandinavian or North Sea Empire: