Starting in 570AD the Saxons moved against the British. The fight began with the Saxon conquest of the south and ended with the war against Rheged.
Ceawlin, Cuthwine and the Conquest of the South
Around the year 570 AD, two Saxon kings, Ceawlin and Cuthwine joined forces to launch a new attack against the British Kingdoms in the West. In a series of battles, the Saxons captured the towns of Durham, Bath, Gloucester, and Circenchester. Their campaigns were finally halted on the edge of modern Wales, on the banks of the river Wye, by a young king name Mouric. Although Mouric would grow to be a great king of the British (Welsh), he would never retake most of the land the Saxons had overrun. By the beginnings of the 7th century, the Saxons were firmly in control of most of the south to the border of modern Wales and the Cornish Peninsula.
Urien of Rheged and the Wars in the North
Unlike the story of the conquest of the south, which is mainly told by Saxon sources, the conquest of the North is mostly told through Welsh tales, and many of these revolve around Urien, his son Owain, and the kingdom of Rheged. By the year 580 AD, Rheged was the most powerful of British kingdoms in the North and covered an area that is today called Cumbria and part of Northumbria. At that time, the Saxon leader Allele launched a major offensive against the British. At first the British were beaten back, but soon rallied under the leadership of Urien. In a series of battles, Urien drove the Saxons all the way back to the island of Lindisfarne. Not for the first time, the British Celts had a group of the invading Saxons on the brink of annihilation, but once again, the Celts destroyed themselves. Urien was assassinated by a political rival named Morcant. This gave the Saxons a chance to recover. For awhile the British continued to fight under Urien's son Owain, but when he died, the kingdom of Rheged died with him. Much of the north fractured and became easy prey for the Saxons.
Although the Saxon conquests between 570 and 615 were not absolute, especially in the north, they were a devastating blow from which the British would never recover. There would be other battles and other great leaders, but the British would never regain any of the land they had lost for any length of time.
As a footnote, some scholars have connected the story of Urien with that of Arthur and even tried to graft the two people into one. Much of this argument is based on his betrayal by Morcant which sounds a bit like the death of Arthur. Unfortunately, this seems highly unlikely if for no other reason than the men appear to be separated in time by over half a century. It is certainly possible however that parts of Urien's story were assumed into the legends of Arthur.
Bibliography
Ellis, Peter Berresford. Celt and Saxon: The Struggle for Britain AD 410-937. Constable, London. 1993
Morris, John. The Age of Arthur: A History of the British Isles from 350 to 650. Phoenix, 1993
Nicolle, David. Arthur and the Anglo-Saxon Wars. Osprey Publishing. 1984
