England became inhabited more than 800,000 years ago, as the discovery of stone tools and footprints at Happisburgh in Norfolk have indicated. The earliest evidence for early modern humans in Northwestern Europe, a jawbone discovered in Devon at Kents Cavern in 1927, was re-dated in 2011 to between 41,000 and 44,000 years old. Continuous human habitation in England dates to around 13,000 years ago (see Creswellian), at the end of the Last Glacial Period. The region has numerous remains from the Mesolithic, Neolithic and Bronze Age, such as Stonehenge and Avebury. In the Iron Age, all of Britain south of the Firth of Forth was inhabited by the Celtic people known as the Britons, including some Belgic tribes (e.g. the Atrebates, the Catuvellauni, the Trinovantes, etc.) in the south east. In AD 43 the Roman conquest of Britain began; the Romans maintained control of their province of Britannia until the early 5th century.
The end of Roman rule in Britain facilitated the Anglo-Saxon settlement of Britain, which historians often regard as the origin of England and of the English people. The Anglo-Saxons, a collection of various Germanic peoples, established several kingdoms that became the primary powers in present-day England and parts of southern Scotland. They introduced the Old English language, which largely displaced the previous Brittonic language. The Anglo-Saxons warred with British successor states in western Britain and the Hen Ogledd (Old North; the Brittonic-speaking parts of northern Britain), as well as with each other. Raids by Vikings became frequent after about AD 800, and the Norsemen settled in large parts of what is now England. During this period, several rulers attempted to unite the various Anglo-Saxon kingdoms, an effort that led to the emergence of the Kingdom of England by the 10th century.
In 1066, a Norman expedition invaded and conquered England. The Norman dynasty, established by William the Conqueror, ruled England for over half a century before the period of succession crisis known as the Anarchy (1135–1154).