“Constantine will be forgotten by everyone in a few weeks time”
Think about this. You start a new job and then receive a double notification that actually the post you had successfully applied for had been reserved for the sons of your predecessors. This is what happened to Roman emperor Valerius Severus - sometimes 'Severus II' - in 306 AD. He was faced by a rebellion in Britain from Constantine the Great and in Italy by Maxentius the Crapulus.
The Roman Empire had gone through some very tough shit recently but under Emperor Diocletian and his buddy Maximian there had been a resemblance of order. It had been a good time to be a Pagan, but not a Christian unless you enjoyed ruthless, if somewhat eccentric torture. In 305 Diocletian and Maximian had hung up their togas for their retirement villas and chariot water clocks. As the Roman Constitution (such as it was) dictated, they would be succeeded by their tried and trusted 'Deputy Emperors' or 'Caesars' as they were officially titled. In this instance it had been Constantius I (Constantine's dad) and Galerius had received the official fluffy purple slippers that indicated their high rank. In turn their old jobs will filled in by Valerius Severus and Maximinus Daia. All looked good so far.
Valerius Severus (judging by the only physical evidence of his existence - a few coins) was another of what could be called the Illyrian Mafia. He came from the same area of the Balkans where Diocletian and co. had come from. He certainly looked like them as well, a close cropped hair and beard and bull neck. Valerius Severus was certainly no pretty mosaic but tried to claim a link to the family of former Roman emperor Septimius Severus.
Staying close with Galerius (they were very heavy drinker partners) ensured Valerius Severus would get close to the top. He did, taking time off to marry and have a son of his own (Little Bull Neck). What Severus's actual qualifications were to be a Caesar or an Augustus (i.e. emperor) hasn't survived. It's a shame, it would have been interesting to read his CV.
What is evident is that Severus was no fan of his boss Constantius and judged rightly that the grey faced emperor was not long for this world. Whilst Severus was in Ravenna (the de facto capital of the Roman Empire in the West), he received a message from Galerius to hunt down and humiliate Constantine who had slipped away from his virtual palace arrest in Nicomedia to look for his father. Severus's soldiers failed and Contantine sneaked away with his father for a working holiday in Britain. It would involve a lot of killing.
Valerius Severus received an angry scroll from Galerius for his failure to capture Constantine. A new message came back from Britain in 306 that Constantius had finally faded away which meant Severus would now become the new emperor. The only hitch was the Constantius's legions had proclaimed Constantine as their new emperor. The Roman Empire now had three emperors...in a few months time it had two more.
Severus prepared his loyal troops to tackle Constantine (now back across the English Channel and residing in Germany). However as he headed over the Alps, a new scroll was sent to him. Another son-of-an-emperor Maxentius had claimed the job was his and by doing this in Rome itself, suggested he had a greater legitimate claim. In case that wasn't convincing enough, Maxentius dragged along his dad Maximian away from his ludo and they became a joint father-son imperial couple.
Valerius Severus therefore faced two rebellions against his imperial authority. He chose to go sandal-to-sandal with the Maxentius-Maximian duo in the hope his friend Emperor Galerius would get involved. Galerius begged off with a poison toe.
The war was quickly over and done. In time honoured fashion, Severus's soldiers deserted him and realising he was up the proverbial creek and paddle-less. The emperor surrendered to his enemies and pleaded he be allowed a private life and a pension. This could be said to have been a might ambitious of Severus as no emperor had managed to resign and stay alive until the recent examples of Diocletian and Maximian (originally). Perhaps Severus was just playing for time, hoping his enemies would fall out and another roll of the loaded dice..who knows.
Maxentius and Maximian agreed to Severus's offer but he first had to do the donkey ride of shame round Rome to show everyone that he was very much an ex-emperor. The victors had Severus chained up in a secure location just outside Rome. Or may be they didn't and killed him in Ravenna. Regretfully, Roman note taking was bad in this time. That Severus ended up dead wasn't in an issue. It happened sometime in September 307 and that was it. Valerius Severus had been emperor for barely a year.
Constantius I and Galerius
Constantine the Great and Maxentius