OK, fast forward a couple hundred years. It is now 450 A.D., and the Roman Empire has collapsed. The Romans moved out, leaving what was left of the Celtics behind.There is no short answer to this question without going through a bit of ancient history first. So I'll try to make it as short as possible then.
At first, what is now England was inhabited by Celtic tribes that came from Central Asia. In about 50 A.D., the Romans came in and invaded England. Some of the Celtics stayed behind, while the rest fled to Wales and Ireland.OK, fast forward a couple hundred years. It is now 450 A.D., and the Roman Empire has collapsed. The Romans moved out, leaving what was left of the Celtics behind.
But the Angles and Saxons were not about to defend the Celtics and get nothing in return for it. They made a deal with the mercenaries that let them bring their families with them. The mercenaries were paid for their effort with land that they could use for farming. When they drove out the Vikings, Picts, and Scots, they began to settle, and eventually melded into one culture, calling themselves the "Anglo-Saxons". Eventually the Anglo-Saxons began to spread out and colonize further north and west and essentially pushed the Celtic tribes all the way out to the very edges of Great Britain. Meanwhile, the Anglo-Saxons continued to spread out, and by 850 A.D., the Anglo-Saxon areas had combined into three kingdoms: Mercia, Northumbria, and Wessex. (See Link to map of Anglo-Saxon England.)
What about their religion?Most of the early Celtic tribes practiced some form or another of Druidism, while a few practiced their own traditions. Druidism was not completely destroyed by Christianity; instead, the practice was simply 'pushed underground' until they later began to re-appear in English literature. When the Romans conquered the native Celtic tribes around 50 A.D., they also brought Christianity along with them, but England was not fully 'Christianized' until around 650 A.D., well after the Romans had left.
An interesting fact is that four of the names of our days of the week in the English language come from the names of four of the Anglo-Saxon Gods.
For more on Anglo-Saxon religion, please go to: Anglo-Saxon Heathenism
The Anglo-Saxons never had much of a written culture, as they passed down their history through folklore. These long epics were passed down from generation to generation and were retold to the people by the 'scops', the poets of the tribe. These epics became the first kind of English literature when they were finally written down by Christian monks in the 10th and 11th centuries.
Anglo-Saxon poetry had certain qualities that distinguished it from other types of poetry:
