An old adage states that Rome wasn't built in a day, meaning that big projects take time to complete. The Roman Empire, as an example, was established gradually and grew over hundreds of years from a city-state to a colossal empire stretching from Britain to Egypt.
And just as Rome and its empire wasn't built in a day, it wasn't destroyed in one either. For centuries, Rome was the center of the empire, but as Rome's fortunes changed, the seat of power eventually shifted away from the city, and the empire permanently split into two separate states in A.D. 395 — one in the east, and one in the west. But why did the Roman Empire divide into the Western Roman Empire and Eastern Roman Empire? And did it happen quickly?
In short, the empire's vast size played a role — its colossal borders made it challenging to govern — but other factors, such as political and social instability, revolts, invasions and incursions into the empire, also led to the split.
