Dark Ages
The Dark ages was a period of time which started around 410AD and lasted for nearly a thousand years. The Romans had just left british shores for the last time, and rather than embrace the new civilization the Romans had brought with them, the indigenous people turned away from it with a vengeance. They preferred to live in their traditional wooden huts rather than the elaborate Roman buildings, they stopped making pottery, they stopped using coins to barter with and went back to their much more simplistic and unfortunately unrecorded way of life.
Fortunately there is enough evidence left behind to gather some insight of their way of life and the laws and beliefs that ruled them.