The Roman Empire occupied Britannia (Britain) for four centuries, providing protection and peace in exchange for submission. Even be-fore the arrival of Christianity, they eradicated much of the native religion, but a few British Druids survived in a hidden sanctuary in the West. The Romans built Hadrian’s Wall on the northern border to keep out the Picts, fierce and mysterious warriors who painted them-selves blue. But in the fifth century, the Romans left, leaving the British to fend for themselves under the leadership of King Vortigern.