10 Greatest Ancient Roman Emperors

The Emperors of Ancient Rome ruled from 27 BC to 476 AD.

However, current thought on the subject often dates the imperial rule back to 53 BC when Julius Caesar formed the First Triumvirate of rulers, from which he quickly became a dictator.

It was after Julius that the term Caesar changed from being a surname to a title signifying imperial rule. Augustus was the first to actually be called Emperor, in 27 BC.

When ranking the greatest of the Ancient Roman Emperors, we have to determine what makes one great. A ruler can be great in terms of accomplishments, but also be terrible in terms of how they treated their subjects.

This list will count down the ten who made the biggest contributions to the empire and western civilization.

1. Caligula (37 – 41 AD)

Caligula is most famous for his increasingly eccentric behavior.

When he first came to the Throne, he enacted several reforms that were very popular with the people and won a few important battles.

2. Nero (54 – 68 AD)

Like Caligula, he is generally remembered for the bad parts of his reign, most notably the great fire that nearly destroyed Rome. Some believe he actually set it.

Prior to that, however, he did much to improve the lives of the Roman people, promoting culture, and entertainment.

In foreign affairs, he preferred diplomacy to battles.

3. Constantine (307 – 338 AD)

The last strong Roman Empire, and the last to rule all of the Empire. He converted to Christianity and began the Christianization of Europe.

He established the city of Constantinople, named for him, which later became the capital of the Byzantine Empire.

4. Diocletian (284 – 305 AD)

After a century of short-termed emperors and constant disputes over the Throne, the Empire was starting to split into two pieces, a western half, based in Rome, and an eastern half based in Alexandria, Egypt.

Diocletian ended up ruling both, briefly rejoining the Empire.

5. Marcus Aurelius (161 – 180 AD)

Generally regarded as the last of the “Good Emperors,” he supported the arts, philosophy, and science.

After his reign, decadence set in and the Ancient Roman Empire began its decline.

6. Hadrian (117 – 138 AD)

Most famous for being Emperor when Hadrian’s Wall was built at what was then the northern boundary of the Empire (now in southern Scotland).

His best contributions were infrastructure. He outlawed the use of torture and built many aqueducts, libraries and theaters.

7. Julius Caesar (54 – 44 BC)

He formed the First Triumvirate with Crassus and Pompey in 54 BC, but with the deaths of Julius’ wife (Pompey’s daughter) in childbirth and Crassus in battle the following year, Julius took the reins of government as a virtual dictator.

His rule major expansions into Gaul (France), and opened trade with the Egyptians, famously fathering a son by Queen Cleopatra. But he was a despot and eventually was murdered in the chamber of the Senate.

8. Trajan (98 – 117 AD)

Trajan’s reign saw the peak of the expansion of the Empire. His rule stretched from the border between England and Scotland (not far from the current one) through all of present-day France, the Iberian Peninsula, the southern half of Europe, into Asia as far east as the Caspian Sea and north to the Caucasus Mountains, and ringed the Mediterranean all of the way around to Morocco.

9. Vespasian (69 – 79 AD)

Came to power after a disastrous year that saw four different emperors, starting with Nero, whose reign ended with a fire destroying large portions of Rome.  

Vespasian oversaw the rebuilding of the city.

10. Augustus (27 BC – 46 AD)

Augustus is considered the founder of the Roman Empire. His uncle and adopted father was Julius Caesar.

He brought stability to Rome after the tumultuous period following Julius’ murder. He oversaw the change from the Roman Republic to the Roman Empire to reflect the expansion of his control over lands as far away as Egypt.

He was also the Emperor during the time of Christ.