How long was The Roman Empire (Western)?

The Roman Empire (Western) lasted 503 years (27 BC – 476) across 5 major phases.

Duration Overview

Duration

503 years

Start

27 BC

End

476 AD

Principate (Early Empire) 311 years

27 BC – 284 AD

Augustus through Crisis of the Third Century. Pax Romana (27 BC–180 AD).

Pax Romana (Golden Age) 207 years

27 BC – 180 AD

207 years of relative peace. Five Good Emperors. Peak territory under Trajan.

Crisis of the Third Century 49 years

235 AD – 284 AD

50 years of civil war, plague, invasion. 26 emperors in 50 years.

Dominate (Late Empire) 111 years

284 AD – 395 AD

Diocletian reforms. Constantine. Christianity becomes state religion.

Final Decline 81 years

395 AD – 476 AD

East/West split. Barbarian invasions. Last emperor deposed 476.

That's 503 years — about 20 generations. No one alive at the start could have known anyone alive at the end.

How long was The Roman Empire (Western)?

503 years (27 BC – 476 AD). From Augustus to Romulus Augustulus. At its peak, ruled 70 million people across 5 million km².

When did The Roman Empire (Western) start and end?

The Roman Empire (Western) began in 27 BC and ended in 476, spanning 503 years.