Around what time did the Anglo-Saxon kingdoms become established in Britain?

The Anglo-Saxon period in Britain is a really pivotal time, marking the transition from Roman rule to the development of what would eventually become England. The Romans officially withdrew around AD 410, leaving a power vacuum. While Anglo-Saxon migrations and settlements began earlier, it took time for these various groups – Angles, Saxons, Jutes – to consolidate their power and establish distinct kingdoms. By AD 600, these kingdoms were pretty well-established. Think of places like Northumbria, Mercia, East Anglia, and Wessex – these were all taking shape around this time, each with its own king and identity. So, while Anglo-Saxon influence was present before and continued to evolve after, AD 600 represents a key point where their kingdoms were demonstrably in place, shaping the political and cultural landscape of Britain. AD 410 is too early because it marks the Roman departure, not the establishment of Anglo-Saxon kingdoms. AD 698 and AD 789 are too late, as the kingdoms were already well-established by then.