## TL;DR

The Roman Empire was the post-Republican period of ancient Rome (27 BCE - 476 CE West, -1453 CE East). At its peak (117 CE, Trajan), it spanned 5 million km² across Europe, North Africa, and the Middle East. The Roman Empire's legal, linguistic, architectural, and political legacy shaped Western civilization.

## Core Explanation

Five Good Emperors (96-180 CE): Nerva, Trajan, Hadrian, Antoninus Pius, Marcus Aurelius. Crisis of the Third Century (235-284 CE): 26 emperors in 50 years. Constantine (306-337): legalized Christianity (Edict of Milan, 313), founded Constantinople. Division (395): Western (Rome) and Eastern (Constantinople) Empires. Fall: multiple causes — political instability, economic decline, barbarian invasions (Visigoths sack Rome, 410 CE), last emperor deposed (476).

## Further Reading

- [The History of the Decline and Fall of the Roman Empire (Edward Gibbon)](https://www.gutenberg.org/ebooks/731)