With the ascending of Egbert to the overlordship, or owner of the title Bretwalda, we can now do a historical analysis of the kingdoms controlled by three of the most powerful Saxon kings of the first century: Edwin, Offa, and Egbert.
This first map shows the kingdom of Edwin, the Northumbrian monarch who gradually brought most of the rest of the Germanic kingdoms under his sway. He took the throne in 616; and by the time of this map, 630, he controlled most of England.
(It is interesting to note that the Kingdom of Northumbria did not extend very far to the west and that the Celts patrolled and controlled this area. Later monarchs would have greater success against the Celts. Edwin did not. It is also interesting to note that Edwin also controlled the Isle of Man and Anglesey, two islands far to the west of Northumbria. In effect, he had control of territories on both sides of the entrenched Celts; but he was unable to press this advantage.)
The second map shows the kingdom of Offa, the Mercian monarch who walked big and talked bigger and considered himself the equal of Charlemagne. Offa didn’t live long enough to see Charlemagne eclipse him by being named Holy Roman Emperor, but Offa did hold sway over most of what we now call England.
Beginning in 757, Offa steadily brought his neighbors and other Germanic brethren under his control, culminating in the acquiesence of Wessex, which brought him the overlordship. Offa, unlike Edwin, conquered Kent. However, also unlike Edwin, he never conquered Northumbria. Offa did, however, give us a long-lasting symbol of his legacy, Offa’s Dyke, which protected Mercia from the Welsh of Gwynedd.
It’s also interesting to note that Wessex by Offa’s time had subdued most of the Welsh influence in Cornwall. This territory, by extension, was controlled by Offa as well. It must be noted, however, that Offa didn’t do much better against the Celts in the north than Edwin did.
The final map shows the overlordship of Egbert, the first monarch to be properly called Bretwalda. Egbert assume the throne of Wessex and went on a rampage, subduing the rest of the Heptarchy in a comparatively short period of time. The map shows the Kingdom of Wessex, along with all the other kingdoms. It is very enlightening to the examine the northern situation: Northumbria (and, by extension, Egbert) now controlled a whole lot of territory formerly controlled by the Celts. The Saxons, it would seem, were more successful at subduing Celts.
So what can we learn from all this? Several things:
The boundaries of English territory was constantly changing. This was still very much a period of time dominated by violent struggles to hold onto settlements and thrones.
The boundaries of the various kingdoms changed, seemingly overnight in some cases.
The boundaries of Celtish and Welsh kingdoms changed as well, depending on who was running Wessex or Mercia or Northumbria at the time.
What we call England today looked very different in 630, 796, and 829.