"Don't forget Constantine (the Great) and then there is : Carausius I 286, Marcus 406, Marcus Carausius II 286-293, Allectus 293, Gratian 407, Magnentius had support of Britannia in 350. So perhaps Brittannia is not the place to send, disloyal generals" -Constantius
I always assumed that Constantine I was a usurper, but my supervisor pointed out to me that's technically not true since Galerius - the senior Augustus - did confirm him as Caesar.
"I believe Gildas refers to Britain as "cradle of Usurpers" and there's definitely something to say about that. The reason why though is quite simple: it was on the edge of the empire and did not have any neighbouring provinces who could send a field army do crush a usurpation during its inception.
Think of it as owning Australia in Risk. Once you have it, it's a great resource and easy to defend". -Dragases
I suppose that's true, its just a case of Galerius having no choice though. When Constantius dies and Constantine is proclaimed Augustus by the army, I suppose he must of realised he might have to face the legions stationed in Britannia and Gaul, he (Galerius ) had already given Severus the rank of Augustus. Again in 307 at the conference of Carnuntum Constantine rejects Filius Augustorum, basically threatening war again, and again Galerius reluctantly recognises him as Augustus, in 309 I think? -Constantius
Oh there's no doubt about it that Galerius had not envisioned a place for Constantine in his Tetrarchy during its inception. Yet Constantius Chlorus' death threw everything in shambles.
"The choice was forced upon Galerius and the fact that he acquiesced in the matter, meant Constantine won official legitimacy. Hence why it's so difficult to qualify him as a usurper." -Dragases
Those are a few quotes of a conversation, but I would like to hear other peoples opinions, concerning Constantine and the provinces of Britannia's frequent usurpers. I hope it will be an interesting discusion