How long did the Roman Empire last?
The Roman Empire lasted about 450 years. It began in 27 BCE and ended in 476 CE.
The empire was built during the time of the civil wars, which followed Augustus’ death. Through a mix of military power and diplomacy, the Roman Empire had expanded to be on every continent by 117 AD. This made it one of Rome’s most powerful empires and an exploiter of its own advantage at different times in history, as well as pushing back against external threats like Western Germanic Tribes, peoples from Central Asia Minor, Sassanid Persians and Huns from what is now modern China or Mongolia with varied success throughout its life span due to being overstretched on some fronts such as the Danube frontier against barbarians at the time of Marcus Aurelius.
The empire was divided among different regions and ultimately evolved into a decentralized state with a Western European culture during its last centuries. In its efforts against Germanic Tribes it was often at war from the Rhine to Constantinople, from North Africa to Syria, but this could never stop further incursions that finally brought its end.
In 476 CE, the last emperor of the Western Roman Empire was deposed by a German Odoacer while Romulus Augustus , probably a viceroy of Flavius Orestes, had already been deposed in 475 CE after a brief rule of 11 months. The Eastern half survived for another thousand years as what was left of the Roman Empire after the Crisis of the Third Century.
Some say that 476 is just a date chosen at random because it reflects less poorly on Rome than other dates, but this is simply not true. There are many important differences between what happened in 476 and earlier events that year that justify why later historians chose to remember this date as the Fall of Rome. For example, 476 was the first time an Emperor had been deposed by a German general on Italian soil. It’s also the year that Odoacer became the first non-Roman ruler to be accepted into Roman citizenship without being raised to the office of consul first.