Roma Invicta: Why were the Romans so good at war?

The Roman Empire lasted over a millennia and controlled most of what is now Europe, the Middle East, and Northern Africa. Officially beginning in 27 BC, the empire would undergo expansion, contraction, and splintering throughout those years, culminating in the fall of Constantinople in 1454.

At the spearhead (figuratively and literally) were the mighty legions of the Roman Empire, which took the fight to the barbarians while also holding and defending Rome’s territories against a myriad of its enemies. But what made the empire and its legions so effective?

Let’s take a look.

1. All roads lead to Rome

“All roads lead to Rome,” as the famous saying goes. While not technically true, the fact that this proverb was first recorded in 1175 and is still used today shows the importance of these structures to the empire.

Roads were not exclusive to Rome, but they took road building to an industrial scale throughout their dominance of the known world. Rome established an enormous network of well-engineering roads from its homeland to its furthest provinces.

These structures stamped Rome’s dominance on conquered lands and served as important logistical infrastructure for Rome’s war machine. They allowed for the relatively rapid movement of troops, supplies, and information across vast distances.

This was critical to maintaining Roman army supply lines and keeping Rome’s (and later Constantinople’s) connection with its empire. These roads were so well built that many are still in use today.

Roman roads were planned and constructed by legionaries, which kept them in peak physical condition and—more importantly—occupied when not engaged in battle. As another proverb states, “The devil makes work for idle hands.”

2. Take and hold

But they had to keep what they’d taken before Rome’s exemplary legions could build roads in conquered lands. And this was another area of civil engineering that Rome excelled at.

Part of Rome’s imperial success toolkit was its ability to construct an extensive network of defensive structures , such as watch towers, camps (called castra ), walls, and other fortifications. Often built to standardized models, these fortified structures enabled Roman armies to safely encamp in hostile territory or readily defend key areas from potential invaders.

Like their roads, these structures were so well built that many still (largely) exist today. One of the most famous is Hadrian’s Wall in northern England today. Roman engineers (and the troops who built them) got so good at this that they could erect mighty structures relatively quickly.

Some key examples are the double circumvallation of Alesia or bridges across the Rhine during the Gallic wars.

3. We are legion

Since the battle was the business end of Rome’s expansion, it should be no surprise that Roman armies were some of the best-equipped and most advanced of its day.

Initially armed similarly to Greek armies of the early days of Rome, various reforms would see the Roman army change how it fought and what it fought with throughout its history. That’s before we even talk about auxiliary or cavalry units, which we’ll exclude for brevity.

The most famous are the Marian reforms of the late Republic. These eventually produced the Roman legionary gear most were familiar with, such as a large scutum , gladius , pilum , plumbata , and segmented armor. In most cases, this resulted in standardization for Rome’s armed forces throughout history.

Roman soldiers were also professionals who underwent extensive combat and discipline training. This, combined with Roman war gear, made them a highly effective fighting force.

But these were only some of the many tools Roman legionaries were equipped with. The equipment also changed throughout Roman history as it adapted to various enemies at home and abroad. This adaptation and innovation were another key part of the Roman armies’ success and the empire’s longevity.

As it happens, the “classic” legionary battle gear would only exist for a few hundred years, with the gladius, scutum, and pilum generally discontinued around the 3rd century AD.

Later, Roman troops, especially from the Byzantine Empire, wore more classically Medieval armor and arms. They also developed advanced technologies for the time, such as the now semi-mythical “ Greek Fire ,” a substance often likened to how modern-day napalm works.

Late Roman units, especially their cavalry, included advanced technologies like the heavily armored mounted cataphracts . These were an early precursor to the mounted knights of the medieval period.

4. Nowhere to hide

Another great area of war that Rome excelled at was siegecraft, specifically siege weapons. While the Roman army was capable of crushing its enemies on the battlefield, it was just as good at taking fortified structures and walled cities.

At this core were various siege weapons, including the famous ballista, catapults (called onegars ), battering rams, siege towers, and other innovations. These machines were designed to either directly smash walls or gates, pick off enemy troops from a distance, and generally create havoc.

Smaller siege weapons (like the scorpion) were also regularly fielded on the battlefield, providing battlefield artillery and fire support.

The Romans also excelled at tunneling and sapping, which enabled them to undermine defenses for particularly stubborn fortifications. Roman engineers were also superb at rapidly erecting siegeworks like earthen ramps.

Some examples of these are still visible today, such as the enormous ramp visible today at Masada. Constructed around 73 AD , this ramp was built to breach the defenses of a mountaintop fortress held by rebels.

5. I am the law

For all the technological and military might of the Roman Empire, perhaps the most important aspect of Rome was how it governed all its subjects. Through a combination of the rule of law, ethics, and active “Romanization” programs, Rome spread its influence through the pen rather than the sword.

The empire’s sophisticated legal system, exemplified by the Twelve Tables and later the Corpus Juris Civilis , ensured consistency and fairness, uniting diverse populations under a common law. In many nations, these are still the foundation of many legal systems.

Initially guided by mos maiorum , ethical governance balanced authority with local sensitivity, allowing for smoother integration of conquered peoples. Additionally, “Romanization” spread Roman culture, language, and customs, creating a shared identity.

It can be argued that Rome’s influence spread more through governance and culture than military conquest.

And that is your lot for today.

The Roman Empire was one of the most important periods in European and Middle Eastern history. Wherever its influence touched, the people’s culture, language, architecture, administration, and beliefs were changed forever.

Much like dinosaurs in the form of birds are still with us today, aspects of Rome are still alive in the cultures and peoples of its former empire.