The Roman Empire was one of the largest and most influential civilizations in history. At its height it ruled much of Europe, North Africa, and the Middle East, governing tens of millions of people and shaping law, language, architecture, and government for centuries to come.

Rome began as a small city state and grew over centuries as a republic, governed by elected officials and a senate. In 27 BC, after a long and bloody period of civil war, Augustus became the first emperor, beginning a system of one man rule that would endure for centuries. His reign opened an era of relative peace and prosperity across the Mediterranean known as the Pax Romana.

At its greatest extent in the second century AD, the empire stretched from Britain to the Persian Gulf, encircling the entire Mediterranean, which Romans proudly called "our sea."

The Roman Empire at its height, shown in red, with its client states in pink.
The Roman Empire at its height, shown in red, with its client states in pink.

A vast network of roads, aqueducts, and planned cities tied the empire together, while a common system of law, a shared coinage, and a widely understood culture allowed trade, soldiers, and ideas to move across three continents. The Italian peninsula sat at the heart of this immense system.

A historical map of ancient Italy, the heartland of Roman power.
A historical map of ancient Italy, the heartland of Roman power.

Rome's lasting genius lay partly in practical things. Its engineers built roads and bridges so well made that some survive today, brought water to cities through towering aqueducts, and perfected a durable concrete. Its jurists developed legal principles, such as the idea that a person should be considered innocent until proven guilty, that still underpin courts around the world.

The empire eventually split into western and eastern halves. The western half fell in AD 476, overwhelmed by internal weakness, economic strain, and migrating peoples, while the eastern half, later known as the Byzantine Empire, endured for nearly another thousand years.

A bust of the emperor Nerva, one of Rome's "Five Good Emperors."
A bust of the emperor Nerva, one of Rome's "Five Good Emperors."

Rome's influence far outlived its political power. Modern legal systems, the Latin roots of many European languages, the layout of Western cities, the calendar, and even forms of government all trace back to the civilization it built, making Rome one of the deepest foundations of the Western world.