A challenge to the imperial authority was hardly unusual in the third century, but for whatever reason, Postumus decides to do things differently.

Rather than marching an army on Rome he shaves off the western provinces, declaring Gaul, Germania, Hispania and Britannia the independent, but still very Roman, Gallic Empire.

Part II of 'Gallienus'

Guest: Associate Professor Caillan Davenport (Head of the Centre for Classical Studies at the Australian National University).