This is the timeline for the Imperium Britannicum alternate history.
475 - 500 AD
- Roman Emperor Julios Nepos is deposed by his general Flavius Orestes. Instead of fleeing to Dalmatia, he heads north to the once Roman lands of Britannia. He is welcomed there by the Romano-British and sets up his capital in Londinium. He immediately starts encouraging positive relations with the native Celtic peoples and restoring Roman law and authority there.
- Ravenna is sacked and Rome is occupied by the Ostrogoths. Western Roman Emperor Romulus Augustus is deposed.
- Months after the fall of Rome, the Eastern Roman Empire acknowledges Julios Nepos as the legitimate Western Roman Emperor, with his seat in Londinium.
- After many years of hard fighting, the Romano-British force the Saxons, Jutes, and Angles off of the southern coast. The Saxons, with nowhere to go, eventually return to their brothers in Saxony.
- The Western Roman Empire now occupied three distinct regions in the British Isles. Brythonia is what occupies OTL England, Dumnonia is OTL Cornwall, and Cambria, OTL Wales.
- Julios Nepos dies and is succeeded by his general Ambrosius Aurelianus.
- Aurelianus and his forces re-establish control over the Isle of Man, in the first major offensive of his reign.
500 - 600 AD
- Aurelianus and his forces defeat another Saxon invasion of Brython, forcing the Saxons to once again return to Germany.