Romano-British is a term to describe the people who inhabited modern day England and Wales, who were under Roman rule. They were conquered by the Romans under Emperor Claudius, when in 43 AD he invaded the region, local resistance died out sometime around 50 AD. Due to the general decline of the Roman Empire, in 376 AD the Romans were forced to abandon the province. Quickly authority devolved into Chaos, previous to this the only real administrators of the province was in the fact the now absent military.
Various petty kingdoms popped up and began to fight amongst each other, and the Picts began to invade as well. Various Romano-British leaders decided to call on foreign forces to help them, such as the Angles and Juts, who were to settle. Eventually these mercenaries were to turn on their employers and conquer them. For a time the Romano-British were confined to areas around Wales, but these too were eventually snuffed out.
One of the famous Romano-Britons was Arthur, the king of the Romans, who fought the Anglo-Saxons in a series of attempts to maintain Roman control over Britain, defeating his foes at the Battle of Mount Badon in 507 CE. However, thirty year later, he was slain by his illegitimate son Mordred and afterwards, the Romano-British were snuffed out in England and Wales.