Did a Forgotten Irish King Conquer Roman Britain?

Added: 2026-05-09

[00:00:00]Hi everyone. I'm in Millfields in Gloucestershire in Cam. So here there is somewhere in the in the immediate vicinity archaeologists have discovered the remains of a Roman villa. Now this Roman villa it appears was abandoned at some point in the latter half of the 4th century. They don't know exactly when but the latest coin that's been found dates to somewhere between 364 and the 390s. So at some point between that uh some point within that window that's when it appears to have been abandoned. Now I was thinking what could possibly have caused the abandonment of this and it's interesting actually it was intentionally demolished. So what could have caused that? Well I don't know and this is just pure speculation but I was thinking maybe it has something to do with the barbarian conspiracy. Now if you don't know what the barbarian conspiracy is also sometimes called the great conspiracy then that is an event which occurred in the 360s. It occurred in 367 or at least that's when news of it was brought back to Rome and they sent an army to go and deal with it. So what happened is it well allegedly there was a conspiracy this grand attempt by the barbarians by the Picts the Scots and maybe some other groups as well to attack and overthrow Roman Britain. So this was very successful at first and it seems that they they basically overran all of Roman Britain right down to the south it would seem and then as a result of that Theodosius the elder the father of Theodosius the great he was sent over to Britain and possibly Magnus Maximus was involved in that as well way before he became a usurping emperor but anyway.

[00:01:45]So they were involved in defeating and putting down this great conspiracy.

[00:01:50]Supposedly it was an organized attempt to overthrow the Romans in Britain that's why it's called the great conspiracy or the barbarian conspiracy.

[00:01:59]Now that event is possibly extremely important and significant in terms of understanding a particular legend about something that happened during Roman Britain. So in Geoffrey of Monmouth's Historia Regum Britanniae he describes an event which on the face of it seems completely fictional. The event in question has to do with Octavius. You see Octavius according to Geoffrey of Monmouth was a young man at the start of Constantine the Great's career when when Constantine the Great became emperor and he set off from Britain to the continent Octavius was a young man and he rebelled against the Romans. And then there there were some conflicts involved between him and the Romans then he ended up fleeing Britain and then he returned sometime later and reestablished his rule there.

[00:02:47]And then according to Geoffrey of Monmouth he held the kingdom until the time of Gratian and Valentinian. Now we don't know what exactly he meant by until the time of Gratian and Valentinian. You see there were two co-rulerships between people of those names. There was Gratian alongside Valentinian the second but there was also Gratian alongside Valentinian the first. So the rulership of of Gratian and Valentinian the first started in the year 367 whereas the rulership of Gratian and Valentinian the second started in 375.

[00:03:27]So we don't know what exactly Geoffrey of Monmouth meant by by those two people whether he was talking about Gratian the first or the second.

[00:03:35]But Peter Bartrum accepted that he was talking about the first Valentinian. And also we don't know if he meant just until the start of their rule or at some point during their reign their co-rulership that's when Octavius ended his rule. We don't know but at some point around the co-rulership of Gratian and one of the two Valentinians that is when Octavius is said to have ended his rule over Britain. Now that is a fascinating claim because it appears completely impossible. You see if there was a a usurper someone who overthrew the Romans and controlled Britain for any length of time you would expect to know about that. You'd expect that we would have clear evidence of that given that we're talking about the Roman era.

[00:04:23]This isn't the dark ages this isn't the 5th or 6th century where we don't really have good documentation for those periods. This is the Roman era so you'd expect us to know about it if this really happened. But here's where it gets really interesting. You see in a previous video I presented the argument that Octavius can be identified as a certain Irish ruler. So he's a ruler who appears in Irish records and he supposedly established his clan in Britain and he lived in the the 4th century. Now there are a variety of reasons to believe that he was actually the same as the person described by Geoffrey of Monmouth as Octavius. You can see the video about that for the full case. But the point is if that is the case and I believe the evidence is strong in support of that connection then that means that given the chronology and given this particular Irish leader's position he is quite likely to have been involved in the barbarian conspiracy. And also not just the not just his position as king and also his chronology but also the attested settlement of his clan in Britain in the late Roman era. So given that the great conspiracy involved barbarians overrunning Britain settling here. So you've got the Irish and the Picts settling or invading and raiding Britain physically establishing themselves in the country. The fact that you've got this attest attestation of this particular Irish ruler's clan in Britain in that very time period indicates to me that he was involved his people were involved in the barbarian conspiracy. So there is a good case to be made that when Geoffrey of Monmouth described Octavius as engaging in this rebellion against the Romans and setting up his own rulership in Britain he's talking about the barbarian conspiracy.

[00:06:17]In other words when he describes Octavius returning to Britain after having fled many years before in the time of Constantine he is talking about the moment when the Irish and maybe together with the Picts and other groups they invaded and overran Britain in 367.

[00:06:37]Actually there's good reason to believe that the start of these events occurred a few years before 367. You see the Roman historian the the 4th century Roman historian Ammianus Marcellinus described how this barbarian conspiracy occurred in 367 but before then he describes how in 364 there were attacks against Britain by the Picts and the Scots and also the Saxons. And then even before then in the year 360 he also refers to attacks against Britain by the Picts and the Scots. So it may well be the case that actually the the Irish together with other groups potentially had already started invading started raiding parts of Roman Britain long before the year 367 maybe as early as 360. Well definitely as early as 360 according to Marcellinus but maybe it was a continual process that reached the climax in 367 that's what I'm suggesting. Now thinking about this particular location Cam in Gloucestershire this is very near where the Severn would take you up through through the country. So any raiders from Ireland who came up through the Severn they would quickly reach this place. So maybe and this is just speculation but maybe the reason that this particular Roman villa was abandoned is because of Octavius's attacks against Britain where he reestablished control over it after having been driven out many decades before. Maybe that legendary figure Octavius the ruler of Britain the supposed father-in-law of Magnus Maximus maybe he is the reason that this Roman villa was abandoned in the late 4th century.

[00:08:28]No one can say for sure I certainly don't know but it's an interesting possibility just something that I was thinking about while I was here and I read about the abandonment of this place. But by all means if you have any other suggestions any other possibilities that you think may be the reason for this abandonment then do feel free to put them in the comments below.

[00:08:48]I would just like to clarify cuz I kind of misspoke a little bit um it's not actually here on this information board where I found the information about the latest coin. The latest coin mentioned here is from almost when I said. This is from uh 348 to 358. But I did want to confirm that that was actually the latest coin which it isn't. So I went to the local heritage center and I found a little booklet that was done by the archaeologists who uh who excavated this uh this area and the actual latest coin is a little bit later that's the one which is from uh 364 to the 390s. But there we go in case you wanted to come and see this information board to find that information yourself it's not here.

[00:09:35]You have to go to the local heritage center in Dursley.