Anglo-Saxon England or early medieval England covers the period from the end of Roman imperial rule in Britain in the 5th century until the Norman Conquest in 1066. Compared to modern England, the territory of the Anglo-Saxons stretched north to present day Lothian in southeastern Scotland, whereas it did not initially include western areas of England such as Cornwall, Herefordshire, Shropshire, Cheshire, Lancashire, and Cumbria.
The 5th and 6th centuries involved the collapse of economic networks and political structures and also saw a radical change to a new Anglo-Saxon language and culture. This change was driven by movements of peoples as well as changes which were happening in both northern Gaul and the North Sea coast of what is now Germany and the Netherlands. The Anglo-Saxon language, also known as Old English, was a close relative of languages spoken in the latter regions, and genetic studies have confirmed that there was significant migration to Britain from there before the end of the Roman period. Surviving written accounts suggest that Britain was divided into small "tyrannies" which initially took their bearings to some extent from Roman norms.