by Peter Kessler, 1 April 1999. Updated
16 May 2018
Ambrosius Aurelianus was, according to the later
legends, high king of the Britons after Vortigern. Although the reality
of his role is clouded by much uncertainty (to say the least!), his
impact on this period in Britain's history seems to have been
The early references
He is mentioned in four early texts, the first and
oldest of which is De Excidio et Conquestu Britanniae, a
sixth century diatribe against the lazy and apathetic British people
and five corrupt British kings, called 'contemptible principalities'.
It was written by the British monk, Gildas, who said that Ambrosius
alone was worthy of praise among his countrymen for his leadership
of the British counteroffensive against the invading Anglo-Saxons.
He is credited with standing against the tide of
invasion and heartening his countrymen by his own courage, and he
seems to have done much to prevent the early break-up of Post-Roman
Britain in the face of a Germanic onslaught which must have seemed
It is possible that he was behind the construction
of the Wansdyke as part of his efforts.
Gildas refers to him as a 'Roman', which clearly
implies his continuation of Roman methods of organisation and
operation. It also reflects upon his family and background, as he
seems to have been brought up in a typically upper class Romanised
British environment, the son of Ambrosius the Elder and his young
Gildas goes on to say that the Saxon advance was
halted by a stunning British victory at Mons Badonicus (Mount
Badon), which is believed to have been fought in the late fifth
century (with the year 496 serving as a pinpoint for the purposes
of information here).
This victory so stunned the German incomers that
an entire generation of peace was bought for the British. This is
borne out in archaeological evidence which finds a sudden cessation
of Saxon advances in the south until the mid-sixth century. The
Anglo-Saxon Chronicle also goes very quiet at this stage.
Effectively, the outcome of the battle destroyed the ability of the
Germanic participants to mount an effective retaliation (primarily,
it seems, the Cantware and Suth Seaxe, and possibly also the Thames
Gildas stops short of naming the commander of
the home forces at Badon, but subsequent centuries have given
that credit to Arthur. This is entirely possible, as Ambrosius
would have been at the height of his power in the third quarter
of the fifth century and, by 496, a successor is more than likely,
with Arthur fitting the bill as the then-battle leader of the
Britons, and perhaps high king or emperor along Roman lines.
With discord building in the country between about 420-450, many
Romano-Britons left in a hurry, burying their wealth in the hope
that they could return in better times to collect it
RULERS OF BRITAIN:
High Kings of Britain
Thames Valley Saxons
Ministry of Propaganda
Introduction to Gildas
What Was Arthur?
The second reference to Ambrosius comes from the
Venerable Bede, an eighth century monk of the monastery of Jarrow,
in the well-written A History of the English Church and
In a statement which seems to support Gildas,
Bede calls him 'Ambrosius Aurelius, a modest man of Roman origin,
who was the sole survivor of the catastrophe in which his noble
parents had perished'.
The catastrophe refers to the Saxon foederati
revolt which occurred in the early 440s, and spread terror throughout
southern Britain, persuading a large chunk of the aristocracy to
emigrate to the more stable Armorican principalities. Bede tells
us that 'under his leadership the Britons took up arms, challenged
their conquerors to battle, and with God's help inflicted a defeat
Nennius, a monk living in Bangor, was the early
ninth century (supposed) compiler of an eclectic mass of material
called the Historia Brittonum.
This is a fascinating document of uncertain
historical reliability, and was the first serious attempt after
Bede to put down the history of the Britons onto paper. Nennius
seems to write about two different figures named Ambrosius, quite
possibly confusing the later commander of the Britons with his
father, Ambrosius the Elder.
In the first case, Nennius refers to a clearly
legendary Ambrosius as being a fatherless child who displayed
prophetic powers before Vortigern (he could well have got his
references confused here as this refers to the life of Myrvin,
the later Merlin of Geoffrey of Monmouth's History of the
Kings of Britain).
Nennius also says that Ambrosius was a rival
whom Vortigern dreaded - but does this refer to the elder
Ambrosius, as this man is described having fought Vortigern at
the battle of Guolloppum (Cat Guolph, Wallop in Hampshire)
around 437 or 438, when internecine warfare broke out between
the two rival factions? Possibly, although the younger Ambrosius
must have been pretty young if it was in fact him.
Shown here is an artist's impression of the Roman
city of Aquae Sulis, a stronghold during the time
of Ambrosius but now buried under modern day Bath
Introduction to Nennius
Historia Brittonum (full text)
In a later passage, Nennius calls the younger Ambrosius 'the
great king of all the kings of the British nation', essentially
confirming his status as high king or emperor of Britain.
What can also be strongly inferred, both from
archaeological and textual evidence, is that Ambrosius came to
control the West Country area around Gloucester, enjoying direct
rule of this region rather than through client kings, allies, or
Nennius has Vortigern making a gift of the land,
perhaps to try and placate a potential political enemy. However,
whether Ambrosius (presumably the Elder) gained the land (which
neighboured Guenet which itself is usually thought to include Mount
Snowdon and Dinas Emrys) as a gift, or whether it was gained after
Vortigern's death, the younger Ambrosius apparently did use the
region as a base.
If this is true, then in all likelihood he passed
it onto his descendants as a single kingdom which only later divided
into the Caer Baddan, Caer Ceri, and Caer Gloui that were conquered
by the West Saxons in 577.
Geoffrey of Monmouth calls him Aurelius Ambrosius,
and says that when King Constans was murdered by the usurper Vortigern,
Ambrosius and his brother, Uther, were smuggled to Brittany (Armorica)
to gain strength to return to campaign against Vortigern.
Death of Ambrosius
In time, Ambrosius defeated Vortigern, warred
successfully against the Saxons and had their leader killed -
Hengist of the Cantware in Kent (in AD 488 - an act which may
have been incorrectly attributed to him).
According to Geoffrey, Vortigern's son, Paschent,
king of Builth, eventually had Ambrosius poisoned (which seems to
support the idea of a date of death for Ambrosius of around 480).
This also fits in with the idea of Arthur (or one of his supporters)
being much more likely to be responsible for Hengist's death and
the victory at Mount Badon.
Whether Ambrosius was a king of the Britons,
a war leader against the Saxons, a Briton, a Roman, all of the
above or none of the above, isn't known for sure outside the
legends and tales about him.
Some have thought that Ambrosius and Arthur are
really one and the same, others that he was Arthur's uncle. The
truth is probably that Ambrosius Aurelianus was a genuine, heroic,
fifth century, Romano-British war leader, some of whose own exploits
have been applied to the legend of Arthur.
Given the confusion by some over their respective
periods of rule, this isn't surprising, but in all likelihood,
Ambrosius the Elder was active between about 410 and the end of the
civil war against Vortigern (circa 440), while his son,
Ambrosius Aurelianus, was active from some point soon after the
date of Vortigern's death in circa 455 to somewhere around
By that time, it seems likely that Arthur led the
battle from around 480-511.
Text copyright © P L Kessler. An original feature
for the History Files.