England became inhabited more than 800,000 years ago, as the discovery of flint tools and footprints at Happisburgh in Norfolk has revealed. The earliest evidence for early modern humans in North West 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 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, England, like 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.