AD 1066-1500 Late medieval

In AD 1066 William of Normandy invaded England and killed the English king, Harold I. The Normans imposed their rule by force, building great castles from which to control the countryside. From this point, the British Isles could be divided into the relatively well-organised heartlands of England and Scotland, and areas of looser political and social arrangements which covered much of Ireland, Wales, western Scotland and the various border regions.

During this period the kings of England and Scotland tried to strengthen their authority in areas where they felt they had claims. They did this through political means but also through warfare. English kings had inherited from the early medieval period a vaguely-defined claim of overlordship of Britain, but until the late 13th century the two kingdoms were usually friendly.

Norman barons colonised the Welsh borders, but the rest of the country was not conquered until Edward I (reigned 1272-1307) began a campaign to bring the other kingdoms in the British Isles under English control. This also created hostility and open war with Scotland. Ireland was never securely conquered — only the territory known as the Pale, around Dublin, was really under English control.

In spite of frequent warfare and recurring epidemics of the Plague, or Black Death, in which almost half the population died, Britain gradually became more prosperous. Towns grew, trade thrived and more people became literate. England and Scotland both developed distinct national identities.