The Roman Empire

Greatest Empire the World Has Ever Known

Did you know that the idiomatic phrase "crossing the Rubicon" means to pass a point of no return, referring to Julius Caesar's decision to cross the River Rubicon and march into Italy at the head of a Roman legion? The act was considered an act of insurrection, and any general doing so forfeited his imperium (right to command).

Flavian Amphitheatre, more commonly known as the Colosseum. The most famous building of the Roman Empire. Rome, Italy.

At its height, the Roman Empire was one of the greatest imperial powers in history, controlling a vast empire incorporating most of continental Europe, Britain, and the Mediterranean islands, most of Asia west of the Euphrates river, and northern Africa.

The economic, cultural, political, and military power exerted by the Roman Empire has had a lasting impact on western civilization, and its decline and fall had a profound effect on world history.

Vincenzo Camuccini. The Death of Julius Caesar, 1806. Museo Nazionale di Capodimonte, Naples, Italy.

At the time of Julius Caesar’s act of treason in 49 BC, Rome was a republic ruled by a powerful senate. However, following a civil war initiated by Caesar, the constitutional balance of power shifted from the Senate to a single leader.

The Roman Republic lasted almost 500 years, and following the assassination of Julius Caesar, who had been appointed dictator perpetuo (dictator in perpetuity), the Roman Empire was established in 27 BC during the reign of Caesar’s adopted son and heir, Octavius.

Unknown. Augustus of Prima Porta, 1st century AD.

Octavius, known by his honorific title Augustus, held overarching military and political power over all of Rome’s provinces and became the first Roman ruler to be granted the title of emperor.

The Roman Empire was considerably enlarged during the reign of Augustus, who initiated a period of prosperity, political stability, and relative peace and security known as Pax Romana (Roman peace).

By around 100 AD, the Roman Empire had reached its largest extent, covering a territory of almost two million square miles and overseeing a population estimated to have been between 55 and 70 million people.

The Roman Empire (red) and its vassals (pink) in 117 AD during the reign of emperor Trajan.

Despite periods of conflict, including war with the Parthian Empire in the east and uprisings by Germanic tribes in the north, Pax Romana was firmly established for approximately 200 years following the reign of Augustus. However, during the 3rd century, Rome entered a period of decline from which it was never to fully recover.

A combination of factors, including internal power struggles, civil war, financial instability, tribal uprisings, and unstable eastern frontiers had left Rome in turmoil, resulting in what historians term the Crisis of the Third Century.

In an attempt to maintain control and stabilize its vast territories, Rome divided its empire into two regions: the Western Roman Empire and the Eastern Roman Empire (later to be known as the Byzantine Empire).

However, the two empires were soon plunged into civil war as they struggled with each other for dominance. Constantine briefly managed to bring peace to the divided empire by unifying the eastern and western halves by 324 AD and making himself the sole emperor.

School of Raphael. The Baptism of Constantine, 1520–1524. Fresco. Apostolic Palace, Vatican City.

By initiating a series of financial, military, and social reforms, Emperor Constantine was able to bring stability back to the troubled empire. He also promoted Christianity, which would later become the official state religion, and founded a new capital city at Byzantium (modern-day Istanbul), which was renamed Constantinople in his honor.

Roman unity, however, did not last long, and the empire’s territories were again divided into east and west just 30 years after the death of Constantine.

As a result of increasingly ambitious invasions from Germanic tribes and destabilizing internal conflict, the Western Empire started to lose its provinces one by one before its final collapse in 476 AD.

The Eastern Empire survived, however, in part because its geographical location made it less vulnerable to attack. The Byzantine Empire finally came to an end following the fall of Constantinople at the hands of Ottoman Turks in 1453 AD.

The impact of the Roman Empire on the development of western civilization is inestimable and includes the beliefs, values, and technology it bequeathed. Rome’s legacy continues to shape our way of life today in the form of town planning, religion, language, law, government, and architecture, among many others.


"I found Rome a city of bricks and left it a city of marble." – Octavius Augustus

"If you must break the law, do it to seize power: in all other cases observe it." – Julius Caesar

"I came, I saw, I conquered." – Julius Caesar

"Make haste slowly." – Octavius Augustus

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