Meredith Mansfield, Author

Ambrosius Aurelianus was almost certainly an historical character. He is the only historical figure names by Gildas, who praises him for turning back the encroaching Saxons. Gildas also calls him the last of the Romans and of something akin to royal birth. And, quite likely, he was a Christian—or Gildas (a monk) might not have praised him so highly.

The Atrebates, and the allied domains of the Regni and the Belgae were early adopters of Roman culture and, unlike some British tribes, remained Romanized and in contact with still-Roman Gaul after Britannia was no longer a province of the Roman Empire. The civitas of the Belgae is possibly the most likely location for Ambrosius.

There seems to have been ongoing tension between Ambrosius and Vortigern. There’s a long defensive structure—a ditch and embankment—called Wansdyke roughly along what may have been the border between the two. Ambrosius is said to have defeated Vortigern at the Battle of Wallop, probably in the neighborhood of what is now called Danebury Hill Fort around 440—or approximately five to ten years before the arrival of Hengist. This would most likely have been in the territory of the Belgae.

Roger of Wendover claims that Ambrosius killed Vortigern in battle. The History of the Britons says that Vortigern’s son, Pascent, ruled in Builth and Gwerthegirnaim (in mid Wales) by Ambrosius’s consent. This would have been a greatly decreased area from that ruled by Vortigern and also suggests that Ambrosius’s influence had extended into Dobunni territory, at least temporarily.

If, somewhere in there, Ambrosius also fought against Saxons, it could have been against Hengest. Or, as mentioned before, the Catuvelauni had likely settled Saxon troops in Surrey, which could also be the Saxons Ambrosius fought.

Interestingly, in about 470, the Regni would be taken over by Aelle to eventually become Sussex (the Kingdom of the South Saxons). The civitas of the Belgae appears to have become Saxon through intermarriage. Cerdic is a nominally Saxon king with a British name. The Belgae would become Wessex (the Kingdom of the West Saxons) and eventually the dynasty that united most of England under Alfred the Great.