Saxon timeline in Britain

One reason the Saxon invaders did not press on into the western extremities of the mainland was that the land was less fertile in these regions. Another was that they had established kingdoms of their own in the conquered territory and were too busy squabbling among themselves. There were seven such kingdoms, known as the Heptarchy: Kent, Sussex, Wessex, Essex, East Anglia, Mercia, and Northumbria. The troubled seventh century saw the following military action take place as part of the on-going politicking:

• 606 Aethelfrith of Northumbria defeats a Scottish invasion.
• 615 Aethelfrith defeats the Britons at the Battle of Chester, separating the Britons in north Wales from their kinsmen in Cumbria.
• 617 Redwald of East Anglia defeats Aethelfrith of Northumbria. Edwin becomes the first Christian king of Northumbria. He defeats the Britons of North Wales.
• 633 An alliance consisting of the British king Cadwallon and Penda, the Saxon king of Mercia, defeats and kills Edwin at the Battle of Hatfield Chase.
• 633 Oswald, Edwin’s successor, defeats and kills Cadwallon at the Battle of Rowley Water, driving the Britons right out of northwest England.
• 641 Penda defeats Oswald at the Battle of Maserfeld. He has Oswald tied to a tree and shot full of arrows. The site becomes the town of Oswestry.
• 654 Oswy, Oswald’s younger brother, defeats and kills Penda at the Battle of Winwaed.
• 685 Oswy’s successor, Ecgfrith, invades Scotland but is defeated and killed at the Battle of Dunnichen Moss. This battle ensured the independence of Scotland from the Saxons.

Dark Ages battles were very much rough-and-tumble infantry affairs with little or no tactical finesse. A commander was considered to have real ability if he occupied the high ground and secured both his flanks, both of which would be second nature to a modern commander.