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 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.