When the Romans left Britain around AD 410, the unconquered native peoples of modern Scotland, Ireland and Wales were presented with the opportunity to pillage what remained of Roman Britain. The Post-Roman Britons did their best to defend themselves by using fortifications. While some Roman forts were maintained, the Post-Roman Britons also created new strongholds, or re-occupied some of the hill-forts first built by their ancestors. The most famous warlord of the 'Dark Ages' was the legendary Arthur. His attempt to unite the Britons in the face of Saxon invaders was doomed, and in a little over two centuries the country had become Saxon England. However, for a few brief decades, 'Arthur of the Britons' did what he could to safeguard the culture and civilisation of Post-Roman Celtic Britain.
