Great Commanders: Julius Caesar

Graham Goodlad analyses the military genius of ancient Rome’s best-known general.


The story of Julius Caesar’s military career is the story of the special relationship between a brilliant commander and an elite fighting force.

The legions of the Late Republic were superb instruments of war. Recruited from the citizen farmers of Italy and the more Romanised provinces of the fast-growing empire, they were largely formed of volunteers, and increasingly of long-service veterans choosing a military career.

Highly drilled, heavily armoured, and tightly disciplined, they had an exceptional esprit de corps. Their weapons system had been refined over three centuries of battle against Samnites, Greeks, Carthaginians, Gauls, and Celtiberians. It comprised three elements.

The scutum was a large oval or rectangular body-shield that could be used to form a defensive shield-wall, to give protection in attack, and as a weapon in its own right, when used to punch an enemy and knock him off balance.

The pilum was a heavy javelin comprising a wooden shaft, a long metal projection, and an armour-piercing triangular head. It could be hurled either in defence or, more typically, in attack, devastating and traumatising the enemy line before contact.

above Roman legionaries in action at the Siege of Alesia in 52 BC.
Roman legionaries in action at the Siege of Alesia in 52 BC. Image: Angus McBride/WIPL.

The gladius was the short, stabbing sword of the legionary, an ideal weapon in close-quarters action, where the aim was to keep up one’s guard, avoid exposing the body, and thrust forwards through gaps in the opponent’s defence so as to inflict deep, deadly wounds to abdomen and groin.

Regiments of free men, fighting in close-packed order, trained to manoeuvre, with superb morale, protected by first-class armour, and equipped with scutum, pilum, and gladius: these were the world-conquering legions of the 1st century BC.

And the greatest commander of the legions in Roman history was surely Julius Caesar.

He was both an imperialist – a conqueror of new provinces – and a civil-war generalissimo, the destroyer of the Republic and the creator of the Empire.

Our special this time reflects both roles. In his biography of the politician-general, Graham Goodlad charts Caesar’s origins, early career, and rise to power, but pays special attention to the Gallic Wars, Caesar’s eight-year campaign to subjugate the Celtic tribes of what is now France and Belgium.

In our second piece, Neil Faulkner analyses the Battle of Pharsalus, in which legion fought legion, and we see Caesar engaged in a very different kind of battle, against his own kind, against men who fight with all the same advantages. Perhaps because of that, we discover in Pharsalus – a battle against the odds, outnumbered more than two to one – Caesar’s greatest triumph, the summit of his genius.

Colossus of the Late Roman Republic

Julius Caesar remains one of a small number of figures from the ancient world whose name lives on in popular memory. On that hazy boundary between myth and history, he is usually remembered either as the lover of Cleopatra or as the victim of his fellow senators, stabbed to death on the ‘Ides of March’.

In the Shakespeare play that bears his name, and which has defined many generations’ view of him, Caesar is described as a superhuman being who ‘doth bestride the narrow world like a colossus’.

Although never crowned emperor himself, he was the ancestor of Rome’s ruling imperial dynasty. And long after his time, Russians and Germans were ruled by monarchs whose titles, ‘Tsar’ and ‘Kaiser’, were variants of the name ‘Caesar’.

As a general in the Classical era, Julius Caesar was rivalled only by Alexander the Great, Hannibal, and Scipio Africanus in the scale of his battlefield successes.

He was not always successful: most famously, although he made two expeditions to Britain, it would be almost another century before his successors established a permanent Roman presence on the island.

Nonetheless, he was the dominant military and political figure of the Late Roman Republic. Caesar’s victory in the Civil War that wracked the Roman world in his last half-decade allowed him to assume dictatorial powers. This led directly to his assassination, a deed carried out by members of his aristocratic peer group, who feared that the victorious general would assume a permanent ascendancy over them.

Caesar’s Commentaries

This article examines the qualities that enabled Julius Caesar to emerge as the foremost commander of his age.

In learning about Caesar’s career, we have a source which is almost unique for a figure from ancient history: his own memoirs of his campaigns, known as the Commentaries. These books, in which he wrote about himself in the third person, are remarkable for their lucid prose style and their detailed factual reporting of events.

Of course, Caesar did not tell the whole truth. He did not reveal his own selfish motives and innermost thoughts; he skated over his failures, and exaggerated his own importance.

Describing how the Romans repulsed a surprise attack while making camp near the River Sambre in Gaul, he writes that

Caesar had to do everything at once – hoist the flag which was the signal for running to arms, recall the men from their work on the camp, fetch back those who had gone far afield, form the battle-line, address the men, and sound the trumpet- signal for going into action.

The books were written in part as propaganda, in order to win political support. Yet, while making allowance for exaggeration, there is no reason to doubt their basic truthfulness as an historical record.

A political general

Caesar was a remarkable man by any standard. He was a skilled politician before all else, whose desire for power was his most consistent, driving characteristic. Passing through a remote Alpine settlement, he is said to have remarked that he would rather be first man in a village than second at Rome.

From an early age, he had shown that he possessed a core of steel. Aged 25, he was kidnapped by pirates and held to ransom. Rather than being intimidated by his captors, he told them jovially that after his release he would return and have them executed – a pledge that he fulfilled after assembling an expeditionary force and sailing back to take the pirate camp by storm.

below Gaul at the time of Caesar, showing the major battle sites of the Gallic War (58-51 BC).
Gaul at the time of Caesar, showing the major battle sites of the Gallic War (58-51 BC). Map: Ian Bull.

Caesar’s early military career was conventional enough, with a period as a junior officer in the East, followed by an independent command as governor of Spain. An important turning point came in 59 BC, when he formed an alliance popularly known as ‘the first triumvirate’ – a system of rule by three men – with Rome’s most powerful political figures. They were Pompey ‘the Great’, his only real rival as a general, and Marcus Licinius Crassus, whose great fortune made him useful to the heavily indebted Caesar.

Late Republican Rome was a dangerous and unstable environment, with both opportunities and risks for the ambitious. An inveterate gambler, Caesar thrived in an arena in which prominent men were as likely to meet a violent death as to reach the top. It was a world in which military command in the provinces was a natural extension of political office-holding in the capital. As Caesar’s own career was to demonstrate, the leadership of Rome’s legions was the essential springboard to power.

Rome and Gaul

Caesar’s greatest achievement, between 58 and 51 BC, was the conquest of Gaul. The Romans had occupied the land known to them as ‘Cisalpine Gaul’ – a region which centred on the Po Valley of northern Italy – for almost a century before Caesar’s birth. Beyond lay ‘Transalpine Gaul’, which presented a much more formidable challenge to the imperial ambitions of Rome’s leaders.

This was an area of some 191,000 square miles, inhabited by a number of Celtic tribes, and roughly corresponding to modern France, the Low Countries, and Switzerland. It was bounded by the Rhine and the Alps in the east, the Atlantic in the north and west, and the Mediterranean and the Pyrenees to the south.

Although often disparaged by the Romans as a land of barbarians, Gaul was in reality a rich agricultural region, with well-built villages and walled towns connected by good roads. The Celts who lived on the Channel coast had fleets of ships which they used to trade with Britain.

Transalpine Gaul’s fatal weakness was the disunity of its various tribes, which Caesar exploited to the full when it was assigned to him as his province. The region was perpetually vulnerable to incursions from aggressive German tribes to the east. And, in the spring of 58, a fresh threat to Roman power arose.

The Helvetii, inhabitants of the area we know as Switzerland, decided to migrate en masse in search of more fertile land to the west. The Roman authorities could not ignore the prospect of an estimated 368,000 people moving into the territories of neighbouring tribes, including the Aedui, who were long-standing allies of Rome.

Appeals for assistance from the peoples threatened by the migration gave Caesar the pretext he needed to embark on a war of conquest. In reality, war offered him a golden opportunity to pay off his debts and enhance his political standing at home.

left The Gauls were among the most formidable warriors in Europe. The Romans had been fighting wars with them for well over a century by the time of Caesar’s conquest of Transalpine Gaul.
The Gauls were among the most formidable warriors in Europe. The Romans had been fighting wars with them for well over a century by the time of Caesar’s conquest of Transalpine Gaul.

Caesar was outnumbered, even allowing for the fact that in his writings he probably exaggerated the odds to make his victories seem more impressive. When he arrived in Gaul, he had at his disposal six legions, totalling at most 30,000 men, with about 4,000 cavalry and some light infantry.

But he had some vital advantages. Friendly tribes like the Aedui supplied his army with food – a critical concern for a commander who was obliged to fight before the harvest season, and who had not had time to organise strategically located supply-depots in advance.

He brutally expelled the Helvetii from the area they had occupied, before driving the Germans back across the Rhine, and then marching, the following year, against the Belgic tribes who inhabited north-eastern Gaul.

The military line-up

Throughout his campaigns in Gaul, Caesar possessed the priceless advantage of leading the best-trained and -drilled military force of his time. Each Roman legion consisted of some 5,000 long-service professional soldiers, divided into ten cohorts, which were the army’s basic tactical units.

Between five and ten former holders of senior civil office, the legates, acted as Caesar’s immediate subordinates. They commanded the legions, secured supplies, and carried out other functions.

Beneath them was a class of semi- professional officers known as military tribunes, although of greater importance on the battlefield were the centurions, each of whom led a century of 80 men. Centurions were usually experienced professionals, appointed for their leadership and administrative skills.

Legionaries were bound to their commander by a combination of harsh discipline and the prospect of material reward in the form of booty and, at the end of their service, grants of land.

Training made a crucial difference between the legionaries and their less well-disciplined opponents, enabling them to stand firm when attacked and to react when necessary without waiting for orders. The legionaries were also superbly equipped, protected by steel helmets, body armour, and large shields, and armed with pila (armour-piercing javelins) and gladii (short stabbing swords).

These experienced citizen troops were supplemented by varying numbers of foreign-born auxiliaries, some of whom were recruited from loyal Gallic tribes, others from further afield, such as Spanish cavalry and Cretan archers.

Against them was ranged an opposition of much more uneven quality. Caesar gave the Gallic warriors credit for their bravery, and their cavalry provided effective shock troops in battle. The Gauls, however, lacked the strong corporate identity of the Romans, and they relied heavily on the prowess of individuals, swinging long swords in a frontal charge.

Provided that the tight formations of the legions held, it was difficult for the Gallic warriors to make much impression, and they were vulnerable to flanking manoeuvres. Nor did they find it easy to wage a prolonged campaign. They lacked the Romans’ logistical skills and sheer staying-power, which gave them a vital edge over a less well-organised foe.

Leading from the front

This disparity in the quality of troops was to prove a decisive factor in the outcome of the Gallic Wars. But success also required an outstanding commander, not only to formulate plans, but also to be an active

presence on the battlefield.

The available sources suggest that Caesar exercised a ‘hands-on’, personal style of leadership. There is little evidence of the systematic use of written orders or of what we might recognise as specialised staff work.

In the search for useful intelligence, Caesar interrogated prisoners and deserters in person, and summoned councils of war when he saw fit. In combat, he moved around the field to assess the changing situation and to encourage his troops, his trademark scarlet cloak making him easily recognisable.

Caesar knew how to win and retain the allegiance of his men. He led them on rigorous marches and exercises as part of their training. This was the more remarkable because his health was uncertain and he is believed to have suffered from epilepsy. He insisted on strict discipline, but was also careful to show his gratitude, and to lavish praise on deserving soldiers.

The spoils of war not only paid off Caesar’s debts and enabled him to buy popularity and political support in Rome, but also allowed him to reward his troops’ courage and loyalty.

During the Civil War, some units, wearied by prolonged warfare, demanded that he discharge them rather than embark on a new campaign. He surprised them by addressing them as ‘citizens’ and reassuring them that they would receive long-promised gifts of land and money. This disarming gesture rekindled their pride as soldiers, and they clamoured to sign up with him once again.

Caesarian celeritas

Perhaps Caesar’s most important quality was his boldness and speed in action. Contemporaries regarded this as the mark of a good leader. A notable example was his crushing of a major uprising of the tribes of north-east Gaul in 54 BC.

Realising that it was vital to recover the initiative, he began operations without waiting for the start of the spring campaigning season. Unable to engage a single rebel army in a decisive battle, instead he deliberately launched a war of terror – burning houses and crops, and seizing people and animals – so that each tribe surrendered in turn.

Having re-established control, he pursued those who had fled eastwards across the Rhine, having his troops rapidly construct a bridge over the fast-flowing river and then overawing the fugitives with a show of strength.

Below The Dying Gaul. This famous Hellenistic sculpture, believed to have belonged to Julius Caesar, depicts ‘the noble savage’ in the form of a fallen Celtic warrior, shown wearing torc, moustache, and lime-washed hair, with shield, trumpet, and broadsword on the ground.
The Dying Gaul. This famous Hellenistic sculpture, believed to have belonged to Julius Caesar, depicts ‘the noble savage’ in the form of a fallen Celtic warrior, shown wearing torc, moustache, and lime-washed hair, with shield, trumpet, and broadsword on the ground.

Caesar was realistic enough to appreciate that an attempt to conquer Germany would have been too large an undertaking. And if he had ever entertained serious thoughts of annexing Britain, this was dismissed after his inconclusive expeditions to the island in 55 and 54 BC. Instead, he decided on the Rhine as a natural and readily defensible boundary for the newly subdued province of Gaul.

Two years later, however, he faced a genuinely serious challenge to Roman rule, in the form of an outstanding tribal chief, Vercingetorix. Caesar’s handling of this uprising finally set the seal on his conquest of Gaul.

Endgame at Alesia

Vercingetorix was a more formidable foe than previous Gallic leaders, since he was able to unite a number of tribes against the Romans, including the hitherto loyal Aedui. He was more single-minded than other chieftains in imposing discipline and organising supplies.

He waged a resourceful guerrilla campaign, avoiding battle and trying to starve the Romans into retreat. He must have been an unusually persuasive figure, since he succeeded in getting his followers to burn their own towns and villages, in order to deny their resources to the enemy.

The campaign was hard fought. Caesar took the town of Avaricum by storm, but suffered a costly reverse in an assault on a hill-fort at Gergovia. But Vercingetorix then made the mistake of allowing himself to be bottled up in the fortress of Alesia.

Archaeological investigations have identified this fortified settlement with Mont Auxois, close to modern Alise-Sainte-Reine, in the Dijon region of eastern France. The stronghold stood on a plateau, with hills rising steeply on three sides and streams to north and south. It was a strong defensive position, and a direct frontal assault would have cost the Romans heavily.

Instead, Caesar resorted to a blockade in order to starve the 80,000-strong garrison into surrender. His fortifications completely encircled Alesia in a process known as ‘circumvallation’.

In the space of three weeks, the legionaries built up to ten miles of 12ft- high palisades, with guard towers at intervals. On the side closest to the fortress, two ditches were dug, one of which was filled with water. Sharpened stakes and lethal clusters of branches were fixed in place near the walls, in order to deprive any Gallic counter-attack of its vital momentum.

Caesar then ordered the construction of a second line of fortifications facing outward. These defences were necessary because he was certain that a cavalry force that had escaped from the beleaguered town would return to the fight, after gathering a relief force further afield.

The siege showed Caesar at his most ruthless. In order to conserve vital food reserves for his fighting men, Vercingetorix drove the women, children, and elderly inhabitants of Alesia out towards the Romans, so that he would have fewer mouths to feed.

Above Plan of the Siege of Alesia, 52 BC, showing the principal Gaulish manoeuvres in the final battle.
Plan of the Siege of Alesia, 52 BC, showing the principal Gaulish manoeuvres in the final battle. Map: Ian Bull.

He was to be tragically disappointed if he had hoped that the Romans would allow them to pass through their lines to safety. Instead, Caesar penned them into a kind of no-man’s land between the fortress and his camp, where they starved to death – a demoralising sight for the increasingly desperate defenders.

The crisis came when a large Gallic relief army came in sight, raising the prospect of a battle on two fronts as Vercingetorix’s forces sallied out of Alesia.

Caesar divided his forces to guard the inner and outer defences, energetically led counter-attacks, and rushed reinforcements to points where they were needed. Running short of food and unable to break out, shortly afterwards Vercingetorix surrendered.

As was traditional, he was later paraded in his victorious opponent’s triumphal procession and ritually strangled. It had been an extraordinary performance on Caesar’s part. From this point on, Roman control of Gaul was not effectively challenged.

The struggle for power

Victory raised Caesar to a pinnacle of prestige which his enemies in the Roman establishment viewed as a deadly threat to their own security. They feared the prospect of his return to Rome, with enough wealth to build a strong power base and to run once again for the consulship, which would give him legal immunity against any attempt at prosecution.

By now the triumvirate had disintegrated, with the death of Crassus on a campaign in Syria in 53. The Civil War which began four years later was a contest between the two dominant figures of the Roman world, one at the head of his veteran army and supported by an alliance of popular forces, the other now the champion of the old senatorial order.

left A romanticised depiction of the surrender of Vercingetorix, the Gallic war leader, to Caesar after his defeat at Alesia. above The assassination of Julius Caesar at the Theatre of Pompey on 15 March 44 BC.
A romanticised depiction of the surrender of Vercingetorix, the Gallic war leader, to Caesar after his defeat at Alesia.

Caesar decided to move pre-emptively against the opposition, even though the action he took placed him outside the law. At the beginning of 49, he signalled his open defiance of the Senate by leading his army across the Rubicon, a small river that traditionally marked the boundary between Cisalpine Gaul and Italy.

The words he is supposed to have spoken – ‘the die is cast’ – were appropriate to a man of his risk-taking temperament. His forces were outnumbered by those on which Pompey could call, although crucially the latter’s armies were scattered over a large area, and most of Pompey’s supporters were demobilised when the conflict began. Nor did they have the fighting quality of Caesar’s battle-hardened veterans.

In a lightning campaign, Caesar won control of Italy, then moved to Spain, before pursuing his rival to Greece in 48. At Pharsalus, he won the victory that is regarded as his masterpiece; it is the subject of an in-depth companion piece in this issue.

He followed Pompey to Egypt, where the latter was killed on arrival by treacherous army officers. Here, Caesar embarked on a personal and political relationship with Cleopatra, whom he secured on the Egyptian throne and who bore him a son.

The Roman legionary of the late Republic

The legionary carried his day’s rations, cooking pots, and tools for building and setting up camp at the end of the day’s march. In battle, in the 1st century BC, he is likely to have worn chainmail, rather than the banded or segmented armour more often shown in illustrations. His head was protected by a bronze or iron helmet with wide cheek pieces. The legionary carried a heavy oval or rectangular shield, the scutum, made of layers of wood and covered in leather, which could be used not only for protection but also offensively, to knock down an enemy. He used a 6ft-long throwing spear, the pilum, and a sword, the gladius, whose 2.5ft-long blade could deliver a devastating thrust against a less well-protected opponent. In well-trained hands, this was a formidable combination of weaponry.

Generalissimo and dictator

There were further threats to be faced down. Leaving Egypt, Caesar defeated Pharnaces, King of Pontus, who had challenged Roman power in the Middle East. In 46, he inflicted a severe defeat on the continuing Pompeian resistance at Thapsus in modern Tunisia, and the following year he crushed Pompey’s sons at Munda in Spain.

The assassination of Julius Caesar at the Theatre of Pompey on 15 March 44 BC.

These victories cleared the way for Caesar to assume the position of ‘dictator for life’ – a title that carried a less negative connotation in Republican Rome than that of ‘king’.

Nonetheless, his many enemies in the governing elite were not reassured. The gulf between him and the rest of his class made him a dangerous figure, and, in March 44, a conspiracy of leading senators resulted in his assassination.

As with many successful commanders, Caesar did not owe his successes to striking tactical innovations, but to a remarkable ability to use the methods and resources to hand. His key qualities were his decisiveness, a readiness to cast caution aside, and his excellent relationship with his troops.

He was capable of great ruthlessness, though he was never wantonly sadistic. When he was cruel – for example, when he ordered the hands of the defenders of Uxellodunum to be cut off, after the capture of this Gallic town – he acted out of a desire to deter further resistance. As a rule, he preferred to win over his vanquished adversaries by a display of mercy.

As the Siege of Alesia showed, he was also a master of military engineering. Underlying all his successes was a keen understanding of human nature and an ability to grasp changing realities. In his own time, and indeed in the military history of the ancient world, he had few, if any, equals. •

Graham Goodlad teaches History and Politics at St John’s College, Southsea.
Further reading
Caesar, The Conquest of Gaul (Penguin Classics, 1982)
Caesar, The Civil War (Penguin Classics, 1976)
Adrian Goldsworthy, Caesar (Weidenfeld & Nicolson, 2006)