What developments in England followed the Anglo-Saxon invasion of Great Britain in 499 A.D?
This is a very broad question. There are many developments which follow this invasion. All of the following had cultural, social, and literary effects on the country: The legendary King Arthur rules a Celtic tribe in 516, and he dies at the Battle of Camlann in 537. Saint Augustine converts the Anglo-Saxon King Ethelbert and establishes a monastery at Canterbury in 597. In 670, Caedman writes his hymns which become the earliest poetry by an English Christian poet whose name we know. Until this point, all poetry was labeled "anonymous". Beowulf is first recorded in writing in 700. The Venerable Bede, an English cleric, writes The Ecclesiastical History of the English People in 730 which is the first record of how people during this time lived daily lives that we have to reference. Then in 793, the Vikings invade Britain.
This is by no means a complete record, but it is a beginning. Check out the links below for more events.