Strategy 14 min read

Why Julius Caesar Didn’t Burn His Boats

Julius Caesar is sometimes incorrectly said to have burned his boats upon landing in Britain. He did just the opposite. Here are six stories from his famous Commentaries.
Vercingetorix throws down his arms at the feet of Julius Caesar (detail) by Lionel Royer

The enemy covered the coastline, leaving no gap for landing. Caesar, believing he could scare away the natives far enough to make some space, ordered his largest warships to charge straight at the beach and run aground, firing everything they had at the enemy.

This worked, but the depth of the water made the Roman soldiers hesitant to disembark. Seeing their reluctance, an eagle-bearer took a moment to pray to the gods and then cried out: “Jump down, comrades, unless you want to surrender our eagle to the enemy; I, at any rate, mean to do my duty to my country and my general.”

And with that he leapt into the water, striding towards the enemy with the legion’s standard.

The soldiers couldn’t bear the disgrace of losing their standard, so they jumped out and followed him. Others in nearby ships saw their advance and, not wanting to abandon their comrades, quickly did the same.

This is a scene from Julius Caesar’s first invasion of Britain in 55 B.C., narrated by Caesar himself in his famous Commentaries. Caesar’s account gives us a glimpse into his strategic mind, and although the presentation may have a political end in mind, it reveals his approach to warfare and leadership through the actions he chose to take.

I found the commentaries especially interesting because the tactics Caesar employs throughout the invasion of Gaul and Britain are the opposite of the “burn the boats” concept—i.e. the idea that you should pick one plan, and intentionally eliminate any opportunity of retreating from it, which is assumed to give you the greatest motivation to succeed. As we shall see, Caesar’s approach is quite different.

1. Always have options: Caesar’s first invasion of Britain

In 55 B.C. Caesar landed on the shores of Britain. After a difficult, protracted battle, he defeated the natives and accepted their peace terms.

Unfortunately, a few days after landing there was a violent storm, which, combined with a high Atlantic tide, knocked the ships around causing significant damage. It also waterlogged the ships that were on the beach. Worse still, since the Romans were planning to return to the continent for winter, they had a very limited supply of food.

Understanding the danger he was in, and suspecting that the British tribes would take advantage of his situation, Caesar set off at once to prepare for the worst. He sent out men to collect corn from nearby fields. He ordered the worst damaged ships to be dismantled, with the materials gathered from them to be used to repair the rest. He requested equipment to be sent from the continent. Very soon all but twelve ships were repaired and ready.

As expected, the native tribes reneged on their peace deal and attacked. After some fighting, the Romans again defeated them, but decided not to pursue them too far inland. After torching nearby settlements, the Romans were again sued for peace, which Caesar accepted, though this time he asked for twice as many hostages. At this point, Caesar decided to he’s done enough and sailed back to the continent to spend the winter.

2. Pick your battles: Caesar crosses the Rhine

Earlier in 55 B.C., Caesar crossed the Rhine and led a short expedition into Germany. The issue was that the German tribes kept raiding Gaul and then retreating back onto their side of the Rhine. In his own words, Caesar wanted to “make the Germans less inclined to come over into Gaul … by showing them that Roman armies could and would advance across the river.”

Caesar built a bridge over the river in ten days and, having made his crossing, left a strong detachment of soldiers to guard both sides of the bridge.

Right away some tribes sued for peace. One tribe, however, the Suebi, sent word for everyone to flee into the forest and for the men to assemble at the center of their territory and prepare for battle.

Rather than fight the enemy at the time and place of their choosing, Caesar simply cut down their crops, burned their farms and villages, and turned back towards Gaul, destroying the bridge he built behind him. As he himself put it, after spending eighteen days punishing the German tribes, “he considered that he had done all that honour or interest required.”1

3. Protect your position: Caesar’s second invasion of Britain

The following year, Caesar returned to Britain. Before setting off, he made some tactical changes based on the lessons of his previous expedition. He adapted the ships to be better suited to the environment by making them lower for quicker beaching and loading, and wider in order to carry more weight. He also left three legions on the continent to guard the ports and provide a supply of food.

The landing was successful, and, after marching twelve miles inland, the Romans captured a strong British fortification.

In a cruel repeat of the previous invasion, a storm again flew over the beach where the Roman ships were docked, and caused significant damage. The ships were knocked about, their cables and anchors unable to hold them in place, and some ships were even cast ashore.

How did Caesar react? He returned at once and immediately got the skilled workmen in his legions to start the repairs. He sent a message to Labienus, the man in charge of the legions he left on the continent, to send more help and to build as many ships as he could on his side of the channel. He even had all the ships dragged onto the beach and enclosed inside a fortification—an arduous task that took ten days to complete.

Having dealt with his escape strategy, Caesar returned to his war with the British tribes, who had now banded together under a new leader called Cassivellaunus. After some fighting, he defeated the new coalition and obtained their surrender.

The effort spent on fortifying the ships paid off. The ships did get attacked while Caesar was away, but the Romans managed to repel the enemy and save their means of escape. Back at the beach, Caesar again decided to cut his stay short, packed his men tightly into all the seaworthy ships, and sailed back to the continent.

4. Don’t listen to your enemy: the destruction of Sabinus’ army

Poor harvest in 54 B.C. led Caesar to split up his army into smaller winter camps scattered around Gaul.

One camp, under the charge of Sabinus, was attacked by the Eburones. The Romans were quick to man the ramparts, repelling the initial attack. The Gauls, seeing the doubtful probability that their assault would succeed, decided to negotiate. Speaking with the Romans, one of the leaders by the name of Ambiorix concocted the following story:

He told them that he didn’t want to attack the Romans because he was personally grateful to Caesar and had no ill will towards them, but he was compelled to do so by the people. He told them that the whole of Gaul had revolted, that all Roman camps were under siege, and that even the Germans had crossed the Rhine and were coming to help. Further, he flattered them by saying that he was not so stupid that he could imagine that he could take the Roman fortification.

He then told them that all the Gauls wanted was for the Romans to leave their village, and that they would be happy to give them safe passage out of their lands. They could go to the aid of the nearby Roman camps if they wished, all that he wanted was for them to leave.

The Roman position was secure, and they still had enough grain to last for some time, so the military tribunes were in favor of staying put and defending the fortification. However, their commander Sabinus was afraid of “a long blockade and a threat of starvation,” as well as the threat of a German attack. He trusted Ambiorix, believing that he would never dare to attack the Romans unless he was compelled, and that they would be able to safely get away.

A long, heated debate ensued. Eventually, the tribunes yielded to Sabinus and decided to move out. Believing the enemy was friendly, the soldiers marched out in a long column, laden with baggage.

The Gauls laid two ambushes, catching the Romans in unfavorable terrain from both ends of the column, thus preventing their escape. In the chaos of the battle, the generals told the men to abandon their luggage and form a circle. Here Caesar makes an interesting observation on the effect of desperate tactics on morale:

Although this measure cannot be condemned in such circumstances, it had unfortunate results: it discouraged the soldiers and increased the enemy’s ardour for the fight, because it clearly indicated an extremity of fear and desperation. It inevitably meant, too, that men were everywhere leaving their units and running to the baggage to look for their most cherished possessions and pull them out, amid a hubbub of shouting and cries.

The enemy used smart tactics. Whenever the Romans charged out of the circle, the enemy would retreat, firing missiles into the newly formed gap. As the Romans moved back to the circle, the enemy would resume their attack. As the battle went on, Sabinus saw Ambiorix and sent messengers asking to discuss terms of surrender. Ambiorix told him he could talk to him if he wished. Taking his military tribunes with him, Sabinus rode up to meet Ambiorix and the other Gaul chieftains. The Gauls told the Roman leaders to lay down their weapons, which they did. As they began to discuss terms, the Gauls surrounded and killed them. Very few Romans managed to flee the massacre and make it alive to the nearest camp.

The lesson of the story is that you should not trust your enemy and should not let fear push you to needlessly abandon a strong position, but it’s also an example of effective persuasion techniques employed by Ambiorix, who: 1) built rapport by presenting himself as a friend being forced to go against his will, 2) flattered the Romans by suggesting that he could never imagine taking their camp by force, 3) framed his demand that Romans leave the camp as a helpful suggestion, and 4) added the threat of incoming Germans to create a sense of urgency in order to force a decision.

5. Don’t surrender a strong position: the rescue of Cicero’s camp

In contrast to this is another story which shows what may have happened if the Romans stayed within the walls of their fortification.

After the destruction of Sabinus’ army, the Gauls were inspired to continue their attack. They gathered more support and moved onto the next camp, which was under the command of Cicero, the younger brother of the famous orator.

The Gauls wanted to take the camp by surprise, but again the Romans were quick to man the ramparts, repelling the attack. Cicero set off right away to construct defense towers with all the timber he had available, and had to build and fight through the night as the attacks would not cease.

Eventually the chieftains asked for an interview, in which they told Cicero the same story they told Sabinus: that the whole of Gaul had revolted, that they did not wish to harm the Romans but were compelled the join the attack. Adding to this, they informed Cicero about the death of Sabinus, using the presence of Ambiorix as proof of the fact. Finally, they told him that all they wanted was for him to leave, and that they would ensure him safe passage.

Cicero replied that “it was not the habit of the Roman people to accept any terms from an armed enemy.” Furthermore, he suggested that the Gauls should disarm and send an embassy to Caesar, asking for peace.

Disappointed, the Gauls started digging a trench and building their own rampart. They also fired incendiary darts, which set alight the thatched roofs inside the fortified village the Romans were occupying. They then tried to scale the walls using ladders, but, despite the heat of the fire and the barrage of enemy missiles, the Romans held them back.

As the siege went on, Cicero tried to get a message out to Caesar. Every messenger he sent out would get intercepted, until eventually one managed to slip past the Gaul defenses and reach his destination. After being informed of the siege, Caesar immediately set off with two legions. He was hoping for a third, but that legion was also facing the threat of siege and thus had deemed it better to maintain their position—a decision which Caesar supported.

Having arrived at the scene, Caesar did not immediately proceed to battle. In his own words:

It would have been very risky to fight on unfavorable ground with such a small force; and knowing that Cicero was now released from blockade, he felt that he had no cause for anxiety, and had better take his time. He therefore halted and made a fortified camp on the most advantageous site he could find.

He made his camp smaller than usual to make his army seem smaller, an application of the principle from Sun Tzu’s Art of War: Appear weak when you are strong, and strong when you are weak.

In the morning, Caesar told his cavalry to attract the enemy towards the camp by engaging and retreating. He told the men in the camp to increase the height of the ramparts and to run around, as if they were afraid. He then told his men to get off the ramparts to invite the enemy closer. At this point the enemy thought Caesar’s army so weak that they began to “make openings in the palisade with their bare hands.”

Caesar then sent out the cavalry, which immediately broke the Gauls, killing many of them. The rest threw down their arms and fled. Cautious as always, Caesar did not pursue them too far “because he saw that he would incur serious losses by abandoning his position.”

6. The value of preparation: the siege of Alesia

The most famous rebellion during Caesar’s conquest of Gaul was under a popular chieftain called Vercingetorix, a smart and resourceful commander who grew to become a serious threat to the Romans.

After a protracted struggle, Vercingetorix ended up losing a field battle and retreated to a stronghold called Alesia. Alesia was situated in an especially strong position, atop a hill with a stream bordering it on either side.

To take it, Caesar had to flip the scales in his favor by laying an impenetrable siege. He built a massive blockade with a circumference of ten miles around Alesia, involving eight camps linked together by fortifications and twenty-three redoubts.

As the blockade was being built, Vercingetorix sent out his cavalry in the night, who slipped past the Romans and traveled to every tribe in Gaul, asking for their support. Vercingetorix asked each tribe to remember his service to them, and told them that if they would not come they would be condemning eighty thousand men to die. He had enough corn to last a month.

Having learned this, Caesar began to expand his siege works, digging a massive trench twenty feet wide. Ramparts and towers were also added along the whole circuit. As many of his men were away collecting corn from nearby fields, Caesar wanted to make it possible to defend the fortifications with fewer soldiers, so he had them dig up a series of five feet deep trenches, filled with sharp spikes. Further pits were dug with sharpened logs placed at the bottom. Having done all that, he had his men build the same thing on the other side, facing outward, in order to prevent the fortification from being attacked from the outside.

Alesia Illustration of the Siege of Alesia, from Charles Anthon (New York: Harper & Brothers, 1862). Although this picture bears little resemblance to the real thing, it shows the multitide of defensive layers Caesar used to wrap around his position (what looks like three rows of trees on either side are spikes)

The relieving army arrived, but lost a cavalry battle. They then tried to break the circuit at night but, after heavy fighting, were again repelled. Finally, Vercingetorix mustered all his strength and attempted to break through the weakest point of the Roman line. The Gauls grew more desperate and the casualties began to rise sharply on both sides. Eventually, after an arduous struggle, the Romans managed to break the enemy. The relieving army fled and Vercingetorix surrendered the following day.


Caesar follows Sun Tzu’s principle that a battle is won or lost before it is ever fought. What matters is what happens beforehand, the points you are able to score before the troops engage: picking the time and place of battle, preparing the troops, preparing supplies, setting ambushes, and so on. The better your preparation, the more advantages you can stack on your side, the smaller is the role of chance in your victory. The victory itself becomes merely the fruit of preparations, the price of which you have already paid.

Caesar never pursues the enemy far into their terrain. Although he undoubtedly makes aggressive moves, he does so from a position of strength, which means always having a well defended base upon which to fall back. If that base is compromised, Caesar returns at once to restore it. Thus he rushes to repair his ships during both invasions of Britain. Thus he decides not to venture too far into Germany, knowing he would find himself disadvantaged on their terrain. Thus he builds a massive circuit around Alesia overloaded with trenches, ramparts and traps of every kind—on both sides—to make even a small force impenetrable to attack.

Caesar succeeds by spending his energy on preparation and having the patience to wait for an opportune moment to strike. Don’t rush to surrender terrain you know to be strong for an uncertain chance of gaining something better. Instead, it may be possible to move to your new position without compromising what you already have.

In Caesar’s case this meant keeping his ships, his bridge, or his current fortification secure before going on the offensive. In your case it might be figuring out how to do something new without having to surrender what you already have, e.g. an entrepreneur can bootstrap a new business without quitting their job, which retains the security of a regular salary. This will involve additional effort. It took Caesar ten days to pull his damaged ships onto the beach within his fortification. But the result is a stronger position via an elimination of risk.

Ray Dalio echoes this idea in Principles:

When faced with the choice between two things you need that are seemingly at odds, go slowly to figure out how you can have as much of both as possible. There is almost always a good path that you just haven’t figured out yet, so look for it until you find it rather than settle for the choice that is then apparent to you.

  1. Caesar narrates his account in third person