Дидий Юлиан
The name originated in the equation of the two co-emperors Diocletian and Maximian with the Roman gods Jove and Hercules. The old-established Praetorian Guard was based at the "Castra Praetoria" in Rome, and had frequently proved disloyal, making and deposing emperors and even on one occasion in 193 putting the Imperial throne up for auction to the highest bidder (cf: Didius Julianus).