by Brian Edward Rise
The sole fifth century Briton named by Gildas (author of sixth century De Excidio Britanniae) and one of the few from any time that he finds praiseworthy. Called a Roman, probably to denote a pro-imperial view, his parents, people of some preeminence, were killed in the Saxon wasting. After the Saxons ceased marauding and withdrew to their settlements, Ambrosius launched a counteroffensive campaign, possibly around 460 CE, that brought about a period of fluctuating warfare climaxing with the British victory at the siege of Badon (Badon Hill) about 500 CE, bringing a more or less stable peace.
Any national status or rank Ambrosius may have held was strictly as a warrior/leader only, judging from Gildas. If Ambrosius Aurelianus was in the service of a high king, Gildas is either ignorant or purposefully neglectful. Adding to the confusion, the Historia Brittonum attributes him with no such military action. Rather, it contains a short reference to Vortigern's fear of him and a longer legend of his display of magical gifts as a child, astounding the court sorcerers. The Historia later refers to him as a King above kings, but this too appears to be legend as it conflicts not only with Gildas but with Welsh tradition which gives Ambrosius the name "Emrys gwledig," gwledig meaning "prince" or "landowner/lord" and in the post-Roman context hints at only a regional power based on command or conquest. In fact, the Historia quotes this Welsh designation and claims that after his feats of magic (rumored to have taken place at a hill-fort named Dinas Emrys up to modern times), Vortigern entitled him Overlord of Wales. History finds a southern kingdom more plausible. An opponent in Wallop, Hampshire, called Vitalinus in appended notes to the Historia, was apparently defeated in 437 CE. However, this makes it highly unlikely Ambrosius was still living or in command throughout the Saxon war up to and including Badon's triumph.
There is naught else in history about Ambrosius but shaky evidence that attributes to him a role in the Briton colonization of Armorica, initializing the process that would result in the region's ultimate metamorphosis into Brittany. Arthur is ofttimes associated with him as a partner or relation. Found in William of Malmesbury (Gesta Regum Anglorum), there is however, no record of it in earlier annals, regardless of the idea's plausibility. Geoffrey of Monmouth gives us his invention of "King Aurelius Ambrosius," uncle to Arthur, while shifting the feats of magic to a youthful Merlin.