In the last piece I told you how this
enormous empire was run by one man in Rome and this could present problems. Just such a problem happened in this year when a guy called Postumus declared himself
emperor of the Western Roman Empire. No such empire existed at the time but his excuse was that he would be able to fight off the Celtic tribes better than
someone based in Rome.
He called his empire the Gallic Empire and it actually remained that way until 274AD despite Postumus becoming posthumous after he was murdered
by his own soldiers in 268AD. Posthumous means something that happens after someone's death.