Dr. David Gwynn

And if Diocles was responsible for imperial safety, you'd have to say he wasn't doing a great job.

Although in fairness, firstly, this kind of event was quite common during the third century and actually killed by bodyguards is the single most common form of death for Roman emperors right through their history.

It goes back to Caligula.

But he was clearly a well-respected soldier, an experienced soldier, and in the right place and well-organized.

Because most of these usurpations, that person then gets murdered in turn.

During the third century crisis, so above all the period between 235 and 284, the average length of reign was less than three years.

There's an incredible turnover of imperial power.

Diocletian is going to hold power for 20 years and voluntarily let it go.

Not entirely.

Unfortunately, we've basically just got a few later very short summaries which really just say that Diocles was making some claim for power and then Carinus dies.

It doesn't seem to be a full-pitched civil war, but in reality, one of the two has to die.

This is a standoff that has to be resolved.

Diocles is the one who has the army support, has the better structures in place.

But exactly how it was all engineered remains very difficult.

It's very unclear whether there is a major pitched battle, whether there's a skirmish, whether indeed Diocles convinces Caius's army that actually Diocles is the better candidate.

It's a problem right through the third century crisis.

But the real difficulty when it comes to Diocletian is, of course, what we've really got is later sources who know what will happen.

trying to give us some kind of reconstruction.

And it's interesting that there doesn't seem to have been a single set narrative for them to draw on.

So we just get these different accounts, like in the Historia Augusta, probably written a hundred odd years later.