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Alexander the Great versus Julius Caesar: A Comparison of Two Of The World's Greatest Military Leaders

Updated: Apr 16

“A good general not only sees the way to victory; he also knows when it is impossible” -  Polybius[1] 

Alexander the Great versus Julius Caesar. Gallic Wars Vercingetorix throws down his arms at the feet of Julius Caesar by Lionel Royer 1899 720X480
Gallic Wars Vercingetorix throws down his arms at the feet of Julius Caesar by Lionel Royer 1899 720X480

Introduction: Alexander the Great versus Julius Caesar

It's the confrontation we history lovers can only fantasise about and talk about—the confrontation that makes us ask more questions than we can hope to answer. Yet within all the mysteries of history remains the tempting allure to try to work out the answers, whether by science, by reason or by pure opinion.

Some of these answers are obscured by time and a lack of documentation, while others are purely obscured because the answers are subjective.

This article is one of the latter kind.

There is no answer—only the articulate compilation of singular facts to form further thought and insight into the subject.

And so, instead of giving a single clear, defined answer to this phantom military engagement, we must study what we do know to draw upon the truth.

So, without any assumptions, let us explore the facts behind these military leaders: their armies, what inspired them, their goals, and how they shaped and revolutionised warfare and history itself.  

Alexander the Great mosaic: Alexander the Great versus Julius Caesar
Alexander the Great mosaic

Alexander the Great

Firstly, let’s look at Alexander the Great.

Born in July 356 BC and son of Phillip II of Macedon, Alexander was from a very early age destined for greatness. His father had forged one of the most advanced military forces in the ancient world and had established Macedon as a stable power within the Eastern Mediterranean. 

Competition in Ancient Greece was tough and those city-states or peoples not progressing and advancing were quickly under threat.  

Throughout his childhood, Alexander had much of his education and philosophy passed onto him from Aristotle. At a very early age, the to-be-king proved himself capable of leadership and authority both in the throne room and at the head of marching men. 

Whilst his father still ruled in the year 338 BC, Alexander displayed courage in the heat of battle, helping rout the fellow Greeks of Athens and Thebes near the city of Chaeronea.

According to our sources, he was the first man to make contact with the opposing Sacred Band of Thebes—an elite military unit with a highly unconventional motivation to do battle.

Did I mention competition was tough?

Not too long after, Alexander’s father was assassinated (not by Alexander) and the young prince rose to the position awaiting him.


Without getting into too many details about his life, relationships and vast conquests, it is safe to say that Alexander has significantly impacted the world today.

Some facts we need to take note of for the ambitious task of comparing this Macedonian King to Julius Caesar are as follows:  

  1. Alexander never lost a battle.  

  2. Alexander commanded both respect and discipline from his fighting men. 

  3. Despite fighting Greeks, Persians, modern-day Indians and many others, Alexander never encountered an army structured like the Roman Maniple or Legions. 

  4. Alexander relied heavily upon his infantry to carry the day and revolutionised the phalanx formation. 

  5. Alexander fought alongside his men on many different occasions, personally leading the companions—an elite contingent of Macedonian cavalry.

  6. Alexander had a knack for utilising the terrain to his advantage and possessed an uncanny ability to predict both his own army's performances and limits and that of his enemy.

  7. Alexander could display an energetic aggressiveness on the field, but when it mattered, patience was not a virtue that went overlooked by the young King. 

  8. Through civil conflicts being an integral component of Ancient Greece, Alexander also learnt of the more subtle political elements of successful warfare—such as keeping friends close and threats eliminated.

  9. Alexander was strong both tactically and strategically—but overall, he was more noteworthy for his tactical genius. Within warfare, the ability to successfully utilise battle formations and execute military manoeuvres on the field is purely tactical. In contrast, to be able to secure supply routes, give your army access to resources, plan a major campaign and use misinformation to lower an opponent's morale, is all strategic planning. Tactics are short-term and strictly combat-based, strategy is the ability to think of everything, including how supportive your allies are, and what the political state of home is like…  

And with that note, we shall look at Julius Caesar.

Gaius Julius Caesar, conqueror of 300 tribes. Based on the Louvre statue of Julius Caesar.
Artist's impression of Julius Caesar. Source: Deviantart.

Gaius Julius Caesar  

Gaius Julius Caesar was born in 100 BC. He became a Roman general and statesman and, unlike Alexander, was not born into particularly high status—although his family name was already cemented in notable pedigree.

Indeed, before his rise to prominence and subsequent fame, he was practically ushered into a life of priesthood to the god Jupiter.

This role was notable, but for Caesar, it was extremely limiting. Upon the death of his father, he was able to escape this somewhat less-than-ideal lifestyle and begin acting upon his more fervent—and sometimes lofty—ambitions. 

Caesar began serving within the Roman army but at this stage saw little active service. He did, however, save a fellow Roman citizen, and consequently win an award for his actions, at the siege of Mytilene.

Upon the death of a more distant relative, Caesar found himself replacing the deceased’s status and was readily accepted into the pontiff, a Roman College of religion open only to those of nobility. This marked a pivotal opportunity for Caesar to embark upon a political career, and be well-received by his counterparts. 

In 63 BC he was easily voted into the position of praetor and went on to make friends and enemies within the political sphere of the ever-adapting Roman Republic. 

Two of these friends are of significant importance: Crassus—who was the wealthiest man in Rome and would later destroy an entire Roman army at the Battle of Carrhae—and Pompey, whom Caesar initially looked up to but would later find himself fighting in one of the bloodiest civil wars in all of history.

Through his political career, it is clear that Caesar learnt a many-sided view of conflict—not just a battlefield and infantry perspective, but also the art of manipulation and subterfuge. 


Around 59 BC, Caesar won Consulship along with one of his most vigorous opponents achieving the same position. Naturally, this was not at all ideal. Later, according to the desire of the Roman Senate, Caesar was sent to Gaul, where he proved his skill as a military campaigner and general.

It is important to remember that in this period of Roman history, the military was firmly linked with the Senate. Consuls and senators exercised great spheres of influence within the army, often leading to a raw lack of combat experience within the hierarchy of Roman Forces. 

However, Caesar was no such leader. Throughout the Gaelic wars, he proved a versatile and cunning commander and earned great respect among his forces. 

Here are some points we must consider when comparing this Roman general, statesman and later self-proclaimed dictator with the King of Macedon:

  1. Caesar campaigned for many years and never stopped adapting to suit terrain,  opponents, weather and any other factors. 

  2. Caesar often set up positions on the high ground, and such terrain proved an essential element in many of his victories.

  3. Caesar, just like Alexander, relied most heavily upon his heavy infantry (legionaries)  to win the day. Many of his legions served under him for years and became extremely experienced.  

  4. Caesar was a tactician and strategist.  

  5. Caesar fought side-by-side with his troops on a number of occasions. 

  6. Caesar never personally fought any army formed or structured like the Macedonian phalanx.  

  7. Caesar displayed a variety of styles: aggression, caution, mercy and ruthlessness.  

  8. Caesar was a great admirer of Alexander the Great and reportedly said when he was younger that at the age of thirty-three, Alexander had conquered half the known world, and he (Julius Caesar) had done nothing remotely similar. According to some sources, he then wept.

We shall now dive quickly into the specifics, structure, and styles of both the  Macedonian and Roman armies. 

The Macedonian Army 

Created by Alexander’s father, Phillip, the Macadonian phalanx was a state-of-the-art fighting machine.

Disciplined infantrymen—called Phalangites—were each equipped with a 5–7 metre long spear called the sarissa and a medium-sized round shield strapped[2] to their forearms, then they amassed into tight blocks. The phalanx was the pinnacle of ancient warfare. 

Cavalry was an integral component of any army fielding the phalanx. To the Macedonians, these cavalry units came in the form of the Companions—the elite Macedonian horse—and others, such as the loyal Thessalian and Thracian mounted combatants, who often get overlooked in the light of their famous companion brothers.

The phalanx was unstoppable from the front. Five to seven metres in length, the sarissa could be pointed straight ahead by the men in the fifth row back and still be poking through the gaps of the shields in the front rank.

The only way to properly defeat such a formation was to either attack its flanks or rear, or to break up its cohesiveness over rough and rocky ground—something which a good commander would try to prevent at all costs.  

The phalanx was the core of any Macedonian force; however, there were also other infantry units. These units comprised archers, slingers and a variation of other ranged infantry.

Sometimes, allied hoplites would also be part of the force. These men typically fought in a similar formation to the phalanx, but they would generally be stationed in reserve.  

It was because of the flank and rear dangers to the phalanx that the cavalry was indeed so important, and Alexander never failed to demonstrate complete mastery of the system his father had created.

Roman troops crossing the Alps. Source: Deviantart.
Roman troops crossing the Alps. Source: Deviantart.

The Roman Army 

The Roman Legions. The Roman legionary system is famous, there is no question about it.

By the mid-hundred BC, the maniple formation was being phased out, and the new system was becoming evident. The old maniple consisted of three major ranks of infantry working their way up in experience. But even by the end of the Punic Wars, the flaws in this system were obvious.

A new style and system was being forged: the Marian Legion

This is the heavy infantry we all think of when someone says ‘Rome.’ 

Heavy infantry—well disciplined and well trained, and equipped with large shields, called the Scutum, javelins (pilum) and short swords (gladius)—became the order of the day.

The structure was impressive, to say the least—with engineers, officers, standard bearers, and men to carry every supply distributed evenly throughout so that every legion, cohort, and century could function together and independently.

The Roman legion was the pride of Rome itself, with countless foes falling under its iron endurability and unstoppable power. Cavalry was once again an important part of the army and structure but the chief job of the cavalry was to protect the infantry—similar to our Macedonian friends.

Light infantry was also included—often allied archers and other foreign units lucky enough to keep their natural way of warfare, rather than being moulded into a signal style. 

The Roman army’s ability to adapt and change to suit climate and weather and terrain was also impressive and no mean feet. At its height, the Roman Empire included desert and snow. So adaptability was obviously necessary for retaining its territories and keeping order.  

The Alexander Mosaic. Battle of Issus (333 BC)
The Alexander Mosaic. Battle of Issus (333 BC)

What Does History Tell Us? 

Having collected these facts, who is to say who would win in an open conflict?

Obviously, being separated by roughly 300 years, such a scenario between these two men and their exact forces is impossible, but let us explore some similar examples we have  from history. These examples are not going to give us a definitive solution as to the  Alexander versus Caesar situation, but they may shed some light on how the armies themselves might have fared.

The first real encounter between the Roman army and the phalanx is the battle of  Heraclea. This phalanx was not the Macedonian phalanx but was practically the same idea adopted by Pyrrhus, the King of Epirus.

The Roman army was also different, but the heavy infantry and disciplinary elements—plus cavalry for support—remained the same.  

The Battle of Heraclea was fought on Roman soil in the year 280 BC. The casualties on both sides were very high, but the Greek phalanx claimed the day. This battle demonstrates a few points.

  1. The Roman army did not buckle under the phalanx as quickly as most other forces.  

  2. The phalanx simply cannot be defeated head-on in open terrain, which may have proved difficult for the Romans to accept, as this was something they were used to excelling at.

  3. The phalanx must be on good terrain to achieve victory.

  4. The Roman infantry would need to improvise to win.  

  5. The result always relies heavily on the commander.  

With these points in mind, we can see what both armies typically need for success. We also see how these forces interact with each other.

Our second battle is almost a replication of the first: the Battle of Asculum. The Greeks once again claimed victory, but not without the repeat of heavy casualties.


In the aftermath, Pyrrhus could not sustain the campaign, and he left. Here are more points we can take away:

  1. The Roman Army would need to adapt. 

  2. The phalanx cannot be beaten on open terrain.  

  3. The Romans do not give up easily.  

  4. The phalanx, if failed to be supported, will struggle.  

Sound slightly familiar?

Let’s look at our third and last example: the Battle of Pydna.

Here we have a battle between the Romans and the Macedonians themselves. That is, Macedonians approximately 180 years after Alexander. The result is the destruction of the phalanx and the fall of Macedon itself. 

So our question should be, what on earth happened? The battle of Pydna was lost for the Greeks because they failed to adhere to the number one principle of the phalanx: stay off rough terrain.

The engagement began in an open plain with a large hill and outcrop to the rear of the  Roman line. The initial engagement went as one might expect: a grind of heavy infantry which, despite the Romans' rigidity and strength, was being won again by the back-to-back, shield-to-shield Greek line.

The Romans as previously, began falling back, unable to press in or even close the distance against the 5-7 metre sarissa. But as the advance got away from them, the phalangites found themselves sloping upward, and the closeness of the formation was all but lost.

This—combined with the unstable[3] Greek horse being routed from the field by the Roman cavalry—doomed the once unbeatable formation.


The points we can take from this battle are the same as previously mentioned. Only this time, the Romans finally managed to successfully exploit the weaknesses of the phalanx.  

From these three examples, we get a good idea of the armies and how they should function, but neither Alexander the Great nor Julius Caesar were present at these engagements. And both of them were masters at working their unique military systems to peak performance. 

Let us take a look at two other examples. These examples are not pitched battles between the Romans and Macedonians, or similar Greeks, but rather one battle in the life of Alexander and one in Caesar’s.

As this article is more about the commanders than the armies, it’s important to realise that no matter how many examples we may have of similar forces battling it out, understanding the leadership that made these generals so great in battle remains more important.

After all, the question is above all else, who would win, not what would win.

The Battle of Issus 

At the battle of Issus, Alexander forced his army across a river under the heat of battle. Personally leading the Companion cavalry on the right, he was able to tie up the Persian light infantry/cavalry and give his infantry time to forge the strip of water.

Once upon the opposite bank, the phalanx emerged in an uneven line, but Alexander was expecting this. The Persians fell upon the phalanx in belief the line was less coherent than it really was.

The discipline instilled in the phalangites made the river crossing possible, and even though both sides suffered, the Persians suffered the worst for it.

Alexander was wounded[4] in the battle, but his timing had been perfect. River crossings attempted with an armed adversary on the opposite bank were often considered a suicide operation in ancient times. Instead, Alexander made this battle one of his greatest victories.


The Battle of Alésia 

The battle of Alésia is famous for good reason. Trapped, and with supplies slowly dwindling, Caesar was able to pull off a miracle operation to both capture the Gallic stronghold he was besieging and fend off the massive Gallic relief force.

The engineering skills of the Romans proved critical in this battle, as they were able to build advanced and sophisticated fortifications in a short time. Surrounded, with enemies on the outside trying to get in, and enemies inside, trying to get out, Caesar was caught between a rock and... another rock.

Somehow, managing to communicate with those inside the fort, the Gauls made a simultaneous attack in two prongs. The Romans began defending on both sides and held off long enough for Caesar to make his move.

He ordered a vicious counterattack by his reserves, who fell upon the Gauls already trapped inside and still scrambling over the ramparts. This attack worked—combined with the attack of a spare unit of Roman cavalry that managed to assault the attackers from the opposite direction. 

From serious trouble to spectacular triumph, Caesar was able to swing the odds to claim victory.


With all these facts, what can we decide? Unfortunately, these facts have not presented a definitive answer, but through my research, I would like to list some additional facts—these ones guiding us toward a possible outcome.

  1. Alexander never lost a battle.  

  2. Alexander would have hardly replicated the same mistakes made at Pydna—one of the only occasions the phalanx was defeated by an army other than another phalanx.  

  3. A favourite tactic of Caesar’s was to utilise the high ground. However, at the battle of Issus, Alexander was able to successfully forge a river and win a battle fighting an opponent on higher terrain.

  4. Caesar was a brilliant strategist; however, if we are looking at a singular pitched battle, campaigning, supply lines, the state of allies, scorched earth policies and other such factors do not come into play. The engagement relies purely on the commander’s skill on the field.  

  5. The life of Alexander and his exploits are recorded by both people who knew him personally and those who did not. On the other hand, Caesar has fewer accounts of his life—the majority of which were written by Romans.

  6. Alexander came closer to opposing a force similar to the Roman legions than  Caesar ever came to fighting an enemy remotely similar to the phalanx. Opposing  Greek mercenaries fought in tight bodies of well-disciplined soldiers, and Alexander was able to successfully defeat these forces.

  7. Both men relied very heavily on their infantry. Unfortunately for Caesar, we witness time and time again where without the advantage of terrain and superior cavalry, the phalanx proved infallible. This—coupled with the fact that the Macedonian cavalry would likely be superior to the Roman horse—bodes ill for the Roman general and statesman.

And so I conclude with much hesitation—and at the same time a certain degree of confidence—that upon the field, in open battle, Caesar, great as he was, would not have been able to triumph against Alexander the Great, King of Macedon. 

I would encourage us all to come to our own conclusions on this matter, so please,  disagree with this hypothesis!

So, in this article, we have witnessed these brilliant commanders and their armies in action. We have seen their improvisation and resourcefulness, and the courage of those men who served loyally under them.

Sadly, we will never know what this hypothetical encounter would have looked like precisely and what its exact result would have been. But it continues to remain a scenario with many possible outcomes—and one of great fascination. 

Alexander the Great versus Julius Caesar.

Two men.  

Two armies.  

Too many results to imagine. 


General Sources: 

  1. Rolfe, John, ed. (1946). "Quintus Curtius Rufus". History of Alexander.  Loeb Classical Library. Archived from the original on 23 September 2015.  Retrieved 28 April 2015. 

  2. Holland, Tom (2003). Rubicon: Triumph and Tragedy in the Roman  Republic. Abacus. ISBN 978-0-349-11563-4. 

  3. Paragon Books (2016). Military Missions: Great Battles & Armies. ISBN  978-1-4748-6776-4.  

  4. Paragon Books (2016). Military Missions: Military Machines. ISBN  978-1-4748-6775-7.  

  5. Watson, Howard (2014). Secrets & Lies: Elite Special Units. A Quantum  Book. Apple Press. ISBN 978-1-84543-591-2

  6. Goldsworthy, Adrian (2003). The Fall of Carthage. Cassel.  ISBN 978-0-304-36642-2. 

Specific Notes and References:

[1] See reference 14 in "External Sources"

[2] His brace, or arm strap is thought to have worked in conjunction with a lanyard or shoulder strap, allowing phalangites to wield their spears with two hands. This way the shield (Telemon) could be prevented from dropping on the arm, but also firmly fixed. 

[3] According to Plutarch, Pereus' heavy cavalry were yet to engage. We do not have sufficient evidence to support this claim but also do not have sufficient evidence to rule it out. 

[4] Arrian, Greek historian and philosopher, approx. 86-169 AD. The Campaigns of Alexander. 

External online sources: 


A special thanks to my brother and best friend who inspired me to study this subject and, to put it simply, is a history book with legs.

*A special thanks to Kings and Generals for their constantly accurate content.  

Researched, compiled, and written by Gabriel Shaw.



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