The early history of Britain was shaped by successive invasions over centuries. The Celts first arrived in Britain around 700-600 BC and built structures like Stonehenge. The Romans then invaded in the 1st century AD and controlled southern Britain until 410 AD, leaving behind constructions like Hadrian's Wall. Following the Romans' departure, the Anglo-Saxons invaded and established kingdoms across Britain in the 5th-6th centuries AD. The last invasion was by the Normans in 1066 AD under William the Conqueror.