In AD 410, war in Europe meant that the Roman Empire was no longer able to take care of Britain. Emperor Honorius told the Romano-Britons that they must look after themselves. A writer named Zosimus records that the British aristocracy (the rich and powerful) then set up their own government and threw out any of the old Roman rulers still in Britain. In the North of Britain, the commander of what was left of the army was known as the Duke of Britain. He probably managed to keep his position of power. His name was Coel the Old. Although the new government may have claimed to control all of Britain, the country seems to have become divided up into lots of small regions. A writer named Prosper speaks of 'tyrants' ruling these areas, usually from a large town at the centre. They were strong or popular men who had set themselves up as local kings without any proper authority. Because no-one felt safe, there was a lot of movement of people around the country. Irish families began to settle in Wales and many Britons sailed to Gaul (now called France) where they started a new country called Brittany.

Click to find out: What happened when King Vortigern took over.