Great Britain as it was known comprised of England, Scotland and Wales as Ireland was a separate country during this period.

At the start of the Middle Ages, England was a part of Britannia, a former province of the Roman Empire.

Formed of the union of small Celtic and Anglo-Saxon kingdoms during the early medieval period, England has long comprised several distinct regions, each different in dialect, economy, religion, and disposition; indeed, even today many English people identify themselves by the regions or shires from which they come—e.g., Yorkshire, the West Country, the Midlands—and retain strong ties to those regions even if they live elsewhere.

It became part of the short-lived North Sea Empire of Cnut, a personal union between England, Denmark and Norway in the 11th century. The Anglo-Saxons migrated to Britain (Pretanī, Prydain) from mainland northwestern Europe after the Roman Empire withdrawal from the isle at the beginning of the 5th century.