Did the Vandals Found the Kingdom of Mercia?

One modern theory suggests that the Anglo-Saxon kingdom of Mercia was founded by the Vandals. Does the evidence really support this argument?

Published: Sep 9, 2025written by Caleb Howells, BA Doctrines and Methodology of Education

Map of Mercia

 

Exactly how and when the various Anglo-Saxon kingdoms in Britain were founded is something scholars continue to research. Nevertheless, the basic fact that they were founded by Angles, Saxons, and associated Germanic peoples from the continent over the course of the 5th and 6th centuries is well established. However, one modern theory argues that the kingdom of Mercia had a unique origin. Supposedly, it was founded by a late arrival of Vandals from North Africa. What is the basis for this idea, and does it really stand up to scrutiny?

 

What Was the Kingdom of Mercia?

map britain anglo saxons early sixth century kingdoms
Map of Brythonic and Anglo-Saxon kingdoms in the early 6th century. Source: Wikimedia Commons

 

The Kingdom of Mercia was, for much of its history, one of the most significant and powerful Germanic kingdoms in Britain. It bordered the Brythonic territory of what is now Wales. The Welsh kingdom of Powys formed its western border, while the Anglian territory of Lindsey and the kingdom of East Anglia were to the east. To the north was probably the Brythonic kingdom of Elmet, before that was conquered by the Northumbrians, while to the south was the Kingdom of Wessex.

 

Over time, Mercia grew much larger. The Mercians were powerful, and their kingdom conquered vast swaths of territory. At its height, it covered a very large portion of what is now England. In some respects, the Kingdom of Mercia differed from the other Germanic kingdoms in Britain. The very fact that they were so powerful has been highlighted as an unusual characteristic by some researchers. For this and other reasons, some researchers have argued that they must have had a unique origin.

 

What Is the Connection Between the Kingdom of Mercia and the Vandals?

twrch trwyth sculpture tony wood
Sculpture of the Twrch Trwyth and his piglets as described in Culhwch and Olwen, by Tony Woodhams, 2008. Source: Nigel Davies via Geograph

 

Specifically, a theory emerged in the late-20th century that the Vandals were actually responsible for the founding of Mercia. According to this theory, the Vandals arrived in Britain in the mid-6th century and carved out some territory for themselves. This then became the kingdom of Mercia. Aside from the general unusualness of the Mercians in comparison to their Germanic neighbors, what specific arguments are used to support this theory?

 

This theory is based on a story found in the Arthurian tale known as Culhwch and Olwen. This story is set in Arthur’s reign, apparently shortly after the Battle of Badon. In this tale, there is a monstrous boar called Twrch Trwyth, which is ravaging Ireland together with its piglets. After Arthur and his men travel to Ireland to defeat it, the boar escapes their clutches and travels to southwest Wales. It then ravages the country across southern Wales before being driven into the Severn from its position just above Glamorgan.

 

culhwch olwen folio 202r osla gyllellfawr
Culhwch and Olwen in Jesus College MS 111, folio 202r, showing Osla Gyllellfawr at the end of the fourth line and the beginning of the fifth, c. 1382-1425. Source: Bodleian Library, Oxford

 

Significantly, one of Arthur’s allies in this story is a figure named Osla Gyllellfawr. He appears in other records as a Saxon leader, as his very name suggests. The fact that a Saxon leader is presented as helping Arthur repel the invasion of the Twrch Trwyth from Ireland supposedly indicates that the Trwch Trwyth represents a unique enemy. This suggests that it was an enemy more powerful than the Saxons.

 

This story bears some similarities to an account found in Geoffrey of Monmouth’s Historia Regum Britanniae, written in c. 1137. He describes how a king from Africa named Gormund attacked the British Isles, first landing in Ireland and ravaging much of that land. He then moved on to Britain itself, devastating the island almost from sea to sea, according to Geoffrey. Given his Germanic name, along with his connection to Africa, it is evident that Gormund is supposed to be a Vandal king. Hence, Geoffrey describes a Vandal invasion of Britain in the 6th century.

 

vandal cavalryman mosaic pavement bordj djedid carthage
A Vandal cavalryman depicted on a mosaic found near Carthage, North Africa, c. 500 CE. Source: Wikimedia Commons

 

However, what is the specific connection between this event and the kingdom of Mercia? In the Historia Brittonum, we find a genealogical record of the kings of Mercia. One of them is named Guerdmund. Given the obvious similarity between the names “Gormund” and “Guerdmund,” this has been used as evidence for the conclusion that the Vandal invasion in Geoffrey’s account led to the foundation of Mercia.

 

Since the Vandals were defeated in North Africa in 534, it seems superficially logical that they may have fled and looked for a new home elsewhere. Hence, the fact that there is a record of what appears to be a Vandal invasion of Britain in that very century, during King Arthur’s reign, is significant. This is the basis for the idea that the kingdom of Mercia was actually founded by the Vandals. However, when we look at this evidence and these lines of reasoning in more detail, do they really stand up to scrutiny?

 

Is Culhwch and Olwen Really a Description of Gormund’s Invasion?

culhwch olwen folio 209v osla gyllellfawr death
Culhwch and Olwen in Jesus College MS 111, folio 209r, showing the death of Osla Gyllellfawr, c. 1382-1425. Source: Bodleian Library, Oxford

 

Let us first consider the issue of the Arthurian tale Culhwch and Olwen. The idea that this refers to an alliance between Arthur and the Saxons to face an even greater threat falls apart upon closer examination. It is true that Osla, a Saxon leader, is presented as Arthur’s ally in this story. However, he ends up dying in the pursuit of the monstrous boar. This is notable since Welsh tradition makes Osla the Saxon enemy who Arthur defeated at the Battle of Badon.

 

If Osla died in Culhwch and Olwen, then this story must obviously be set after that battle. As scholar Peter Bartrum pointed out, this evidently means that Culhwch and Olwen is set after Arthur had defeated and subdued Osla at Badon. This means that his appearance in Culhwch and Olwen is not as a reigning allied king but as a defeated and deposed ruler. Hence, there is nothing about this that suggests that the monstrous boar represented some threat that scared the Saxons so much that they allied themselves to the Britons.

 

map coedkernew newport wales
Map showing Coedkernew in Newport, Wales, a remnant of the region of Cerniw in Gwent. Source: Street Map

 

Furthermore, the idea that this story has anything to do with Geoffrey of Monmouth’s story of Gormund’s Vandal invasion does not stand up to scrutiny. Geoffrey directly places that event in the reign of Ceredic, one of the high kings of Britain after Arthur had already died. This would appear to be the historical Ceredic of Elmet of the late 6th century. In any case, the Vandal invasion definitely occurred after Arthur had died. This does not fit the story in Culhwch and Olwen.

 

Additionally, Geoffrey of Monmouth’s account makes it clear that Gormund was allied with the Anglo-Saxons of Britain. He even says that Gormund, after his devastating attacks on the country, handed Lloegr (England) over to the Saxons. In contrast, the story of the boar in Culhwch and Olwen states clearly that the boar was driven from Cerniw (either Cornwall or Gwent) and fled into the open sea, never to be seen again.

 

Did Gormund’s Supposed Vandal Invasion Really Lead to the Founding of Mercia?

king peada mercia john speed
Peada of Mercia, son of Penda, depicted on John Speed’s Saxon Heptarchy Map, 1611. Source: Cambridge University Library

 

What about the supposed connection between Gormund’s invasion and the founding of Mercia? Even if we dismiss the connection to the story in Culhwch and Olwen set in Arthur’s reign, might Gormund nevertheless be identifiable as Guerdmund, the alleged ancestor of the Mercian kings? The reality is that Guerdmund of Mercia in the Historia Brittonum is definitely not identifiable as Geoffrey’s Gormund, king of the Vandals.

 

According to the Historia Brittonum, Guerdmund was the ancestor of Penda, son of Pybba. This Penda of Mercia is a well-known king, and he was born in c. 606. Notably, the Anglo-Saxon Chronicle provides a fuller version of his ancestry, showing that the version in the Historia Brittonum is significantly abbreviated. The Guerdmund from the Historia Brittonum corresponds to Waermund in the Anglo-Saxon Chronicle’s version. Based on Penda’s estimated date of birth, his ancestor was probably born in the 4th century, long before Geoffrey’s Gormund. Hence, Gormund, the legendary Vandal king, cannot be Guerdmund, the legendary ancestor of the Mercian kings.

 

Why Mercia Probably Wasn’t Founded by the Vandals

coin gelimer king vandals
A coin of Gelimer, the last king of the Vandals known to history, c. 530 CE. Source: Wikimedia Commons

 

Based on this evidence, what can we conclude? We can see the idea that Mercia was founded by the Vandals is based on a comparison between Culhwch and Olwen, Geoffrey’s account of Gormund’s invasion, and the Historia Brittonum. However, when we examine this evidence more closely, we can see that it does not stand up to scrutiny. There is no evidence that the account of the boar in Culhwch and Olwen represented some greater threat that forced the Saxons to ally themselves with the Britons. Rather, the Saxon Osla was evidently serving Arthur after being defeated at Badon.

 

Furthermore, the details in Geoffrey’s account about Gormund make it clear that it cannot be identified as the attack of Twrch Trwyth. Even more significantly, while Geoffrey does claim that Vandals invaded Britain in the 6th century, he does not say that they founded Mercia. The supposed connection between Gormund and the legendary ancestor of the Mercian kings, Guerdmund, is impossible for chronological reasons. Therefore, there is really no evidence that the kingdom of Mercia was founded by the Vandals.

photo of Caleb Howells

Caleb Howells

BA Doctrines and Methodology of Education

Caleb is a published history author with a strong interest in ancient Britain and the Mediterranean world. He holds a BA in the Doctrines and Methodology of Education from USILACS. He is the author of "King Arthur: The Man Who Conquered Europe" and "The Trojan Kings of Britain: Myth or History?". Caleb enjoys learning about history in general, but he especially loves investigating myths and legends and seeing how they might be explained by historical events and individuals.