If Rome's first invasion of the British Isles in 55 BC had been a mere reconnaissance expedition, then its successor in the following year took on more of the appearance of a conquest. Julius Caesar does not say as much in his account of the war, rather he maintains that it was intended only as a short-term campaign to punish those Britons who had fought against him during the numerous battles with the Gauls. As stated previously, it is doubtful whether the support that the Britons had offered, if it existed at all, could have been so considerable as to court such a response, and there is evidence to suggest that Caesar was instead motivated by plunder, if not the formation of a Roman province in Britain, at least on the southern coast.
If we are to believe Caesar's stated objective, then we must wonder at the sheer size of the force that he took to Britain in 54 BC. During the previous summer he had led two legions across the Channel, but now he had five at his disposal with 2,000 Gallic cavalry in support, amounting to two-thirds of his entire army; the remaining three legions and 2,000 horse remained in Gaul, guarding the supply lines and keeping a close eye on the restless tribes. This was an extraordinary force for a mere foray amongst the natives of an insignificant land; the Roman Conquest of Britain in 43 AD, its aim being nothing less than the capture of the entire island, was carried out with just four legions. There is also the none too small matter of the fleet that sustained Caesar's expedition; in contrast to the 80 vessels of the first invasion, in excess of 800 were built for the second. Furthermore they had been custom-made for the purpose; being wider than is typical to enable them to carry more substantial loads, and, in response to the difficulties that his men had experienced during the landing of the previous year, Caesar had specified the shape and size of the hulls so that they could be loaded faster and beached more easily.
Various problems arose that posed a threat to the new campaign. Caesar first had to counter border raids in Illyria followed by various dissenters in Gaul, and when the fleet was ready to sail, unfavourable winds in the Channel delayed his departure for a month. When his army finally put to sea, all vessels leaving together, they made a successful landing on the east coast of Kent, somewhere between what is now Sandwich and Deal. The landing was utterly unopposed, in stark contrast to the first invasion. Yet it could be that the Britons had once again discovered when the legions would set sail and what their destination would be, for when Caesar came ashore he learned that an army had been assembled there with the intention of opposing him, but they had since took to their heels, having been, quite understandably, overawed by the vast armada that filled the horizon.
Even so, the decision to abandon the beach seems to have been more along the lines of a strategic withdrawal than a headlong flight for their homesteads, because the Britons did not abandon the area at all but retired to nearby high ground with the intention of regrouping elsewhere. With such an enormous force opposing them, perhaps they understood that any attempt to fight on the shoreline would inevitably result in their being flanked by subsequent landings further along the beach, which could easily result in their being surrounded and utterly destroyed. The beachhead, therefore, was surrendered without a fight and the Britons began to make their preparations for a stand further inland where the terrain would be to their advantage.
Their swift disappearance did not prevent the Romans from taking some prisoners, perhaps as a consequence of cavalry patrols overrunning stragglers as they scouted beyond the beach, and from these Caesar learned where the Britons were gathering. Leaving a strong force behind to guard the fleet, he marched his army through the night, and by daybreak, having advanced 12 miles, they confronted a force of British chariots and cavalry on an area of high ground next to a river, almost certainly what is now the River Stour, probably in the vicinity of Canterbury.
Due to the ambiguous nature of Caesar's account of these events, it is difficult to form a clear picture of either the size and consistency of this British force, or of the engagement that followed. He says that they had been placed there to "bar his way", which suggests that they were located on the opposite bank. Geographically this makes very clear sense, because the River Stour envelops eastern Kent and the Romans would have to cross it at some point to progress further west. We can see the strategic thinking of the Britons in choosing to make a stand here; it would be very difficult for the Romans to use their superior numbers to flank them, and the act of fording a river naturally fragments an army and funnels it into a very restricted space on the other side where it is difficult to manoeuvre. The Britons defending the far bank, by contrast, would have all the room they needed to hold the Romans in the river. Or at least this is the theory, because Caesar goes on to say that the British cavalry attacked from their favourable position but were repulsed by his Gallic horse. He makes no mention of ordering a crossing the river, but he surely must have done, first because of geographical necessity, and it would make no sense for the Britons to abandon their profitable position on the other side. It is likely, therefore, that Caesar sent the cavalry across the river to chase them away, and it was at the inevitable bottleneck on the far side where the Gauls were waylaid.
Caesar does not indicate the size of the British force, but we can perhaps extrapolate that it was not at all significant if the battle could be decided by a mere cavalry skirmish. There is no mention of there being any infantry present, although the line "the enemy, who advanced to the river with their cavalry and chariots" may imply that there were other elements in support. If there were, it is curious that they were not able to throw back the Gauls, who surely would have been vulnerable to infantry with little room to manoeuvre on the far bank. It may be that the Britons were an all-cavalry force, who intended to discourage the Romans from crossing the river by their mere presence, or else fight a quick skirmish and hit them when they were vulnerable before diving for cover. But perhaps they were simply the local tribe, who, with what little arms they had in contrast, made a stand against the juggernaught on ground of obvious strategic importance. It is possible that they could also have been the vanguard of a much larger army of the tribes that had not yet been assembled: Caesar was not a man liable to hesitation, and throughout his campaigns in Gaul he marched his men over long distances in a very short space of time so that he could confront the enemy before they had mustered anything like their full strength; surely the Britons could not have imagined that he would be so swift as to advance his army 12 miles inland, during the night, just hours after landing.
It seems logical to assume that they were either a weak vanguard or the local tribe, because the repulsed Britons did not scatter to the wind as cavalry fighting a delaying action might, but instead fell back a short distance to a fort. This may have been their home and the natural place to which to flee, or if not, then it was a sanctuary where the infantry could regroup and be spared the horrors of a pursuit by the Roman cavalry. Perhaps they hoped to buy time by making a stand here, until the tribes could gather and come to their aid? If so then they were to be disappointed because Rome was not prepared to dally with a siege, rather the attack began immediately. The stronghold appears to have been a hill fort shrouded in woodland: Caesar describes it as "a well-fortified post of great natural strength, previously prepared, no doubt, for some war amongst themselves, since all the entrances were blocked by felled trees laid close together". This certainly describes what we have come to recognise as a hill fort, although they are traditionally sited on high ground with unobstructed views of the terrain for miles around, yet here is one that has had trees deliberately allowed to grow all around it. Why? Well the implication is that the woods added to the defensive capabilities of the fort by removing the blessing of visibility from the enemy. The local tribesmen would naturally know the lie of this land perfectly; where all the tracks were, where they could hide, where ambushes could be set, etc. It is a hunting ground, from which warriors could suddenly charge from amongst the trees at an unsuspecting enemy, cut him to pieces, and then vanish into the undergrowth before a response could be organised. Caesar confirms that this was the case; "Scattered parties made skirmishing attacks out of the woods, trying to prevent the Romans from penetrating the defences." How successful they were is not recorded, what is said, however, is that the VII Legion formed a "Testudo", the famous tortoise formation with locked shields placed over their heads, and began to create a bridge into the fort by piling earth against its ramparts. The use of this formation suggests that the Romans were under a degree of missile fire from the defenders, most likely sling stones and javelins. Hill forts were never designed to impede an army with anything like the organisation and siege-skill of the legions, and so it is of no surprise that it duly fell.
The Britons were then driven out of the woods, but they were not pursued far, however, because Caesar very wisely decided to honour the tradition of using the final hours of daylight to build a fortified camp, lest an enemy should attack during the night and catch him at a disadvantage. In the morning, he formed three columns of infantry and cavalry and sent them in pursuit of the fleeing Britons. They soon caught sight of them, but before they could engage they received word from Caesar ordering them to return to the camp immediately. Lightning may not strike twice but the unfamiliar seas of the English Channel most certainly do: as had occurred during the first invasion, a storm had broken out and the Roman fleet had been badly mauled; 40 vessels had been lost and many of the rest were damaged. Once again, the campaign was barely underway before it had to be halted. Craftsmen were summoned from throughout the legions and the repairs began immediately, but the prosecution of the war was delayed for a further ten days because Caesar ordered that all the ships should be beached to afford them better protection, and consequently a stockade had to be constructed around them.
When he returned to the front and prepared to resume offensive operations, Caesar found that the Britons had since mobilised a real army to stand against him. Cassivellaunus, leader of an unnamed tribe who occupied a region that was later known to be held by the Catuvellauni, had spent several years at war with his neighbours as he tried to secure dominance over them, but the arrival of the Romans was deemed a bigger threat; tribal differences were put to one side, therefore, and he was given the supreme command of their forces.
Caesar continued to push westward and there followed a "fierce encounter" between his Gauls and the British cavalry and chariots. The Romans were said to have had the best of it on every part of the battlefield and then drove the Britons into the woods, killing a great many, but they in turn lost a number of their own by pursuing too far and getting caught. The battle may have been much more inconclusive than Caesar writes, because the Britons did not suffer so badly that they were routed, on the contrary they simply regrouped in the woods and attacked again. Perhaps this fact owes more to their fighting spirit than the course of events, because the Romans were clearly of the view that the Britons had been chased off and the danger had passed, for they had relaxed and were going about the business of building a camp when, all of a sudden, the enemy in their battle fury came flying out of the woods at them. Two cohorts were sent to reinforce the outpost that had been mobbed, and they were presumably rescued, but Caesar notes that "the men were unnerved by the unfamiliar tactics, and the enemy very daringly broke through between them and got away unhurt." Further cohorts were sent in before the Britons were finally pushed back, and the fighting must have been severe as a military tribune, Quintus Laberius Durus, is named as being killed on this day.
Caesar goes on to describe the British tactics and the difficulties that his men faced. "Throughout this peculiar combat, which was fought in front of the camp in full view of everyone, it was seen that our troops were too heavily weighted by their armour to deal with such an enemy: they could not pursue them when they retreated and dared not get separated from their standards. The cavalry, too, found it very dangerous work fighting the charioteers; for the Britons would generally give ground on purpose and after drawing them some distance from the legions would jump down from their chariots and fight on foot, with the odds in their favour. In engaging their cavalry our men were not much better off: their tactics were such that the danger was exactly the same for both pursuers as pursued. A further difficulty was that they never fought in very close order, but in very open formation, and had reserves posted here and there; in this way the various groups covered one another's retreat and fresh troops replaced those who were tired."
When we think of warfare in the Celtic world, we imagine reckless charges by an army of individualists, but these last lines of Caesar's give the lie to this impression. He mentions warriors fighting as a group, formations, and the tactic of a feigned withdrawal to lure the enemy into an ill-advised pursuit, only then to become ensnared in a planned counter-attack. Furthermore, the one thing that we absolutely do not associate with their brand of warfare is the concept of a strategic reserve; a considerable force of men sitting inactive on the fringes of battle while the fight rages before them, where others are winning the honour and renown that could be theirs to boast of. Clearly they were perfectly able to repress these impetuous feelings which should have drawn them to combat like iron filings to a magnet. Instead they waited patiently, either to leap to the assistance of comrades who were in flight and so afford them the chance to reform and join battle again, or simply to take their turn in the line to give others a moment to rest. This rotation of tired troops during a battle is something that we more associate with the likes of Rome, not the primitive unwashed of the northern wilds.
The command and control aspects should not be overlooked here either. It can be accepted that a reserve force coming to the aid of those in flight is something that could happen without any particular chain of command to instruct it, but to relieve forces in the battle line who are deemed to be tired requires a system of orders and timing. A group of soldiers cannot simply withdraw from a fight of their own accord and leave a gaping hole in the line, threatening the flanks of one's neighbours; consequently it has always been a feature of warfare that it is very easy for units to join a battle, but very hard to arrange to pull them out of it. To orchestrate this requires orders from a war leader, and these orders must be obeyed and carried out punctually. This requires runners to carry instructions, and leaders of each warband to receive them.
Despite the fierce fighting that had taken place on that day, the Britons had still not been driven from the battlefield, instead they took up a position on several hills close to the Roman camp. During the following morning they were still active in harassing the Gallic cavalry, but it was noted that they did so in smaller numbers and did not press their attacks with such enthusiasm. It was the lull before the storm; their forces were lying in wait elsewhere. Caesar gave one of his generals, Gaius Trebonius, the command of three legions and all the cavalry, and ordered him off on a foraging expedition. At midday, Trebonius was attacked by a great host of Britons, and he must have walked into a trap because his men were being assailed from every direction. Caesar intimates that they were in great difficulty as he states that the attacks were carried right up to the standards of each of the legions. The Romans prevailed, however, first through a strong counter-attack by the legionaries and then by what Caesar describes as a devastating charge by the Gallic cavalry which utterly routed Cassivellaunus' army. The pursuit was very close and the Britons, who must have suffered many losses, were given no opportunity to reform and charge afresh. This was a decisive victory in Caesar's campaign as it essentially broke the back of the most serious resistance.
Thereafter the Romans attempted to attack Cassivellaunus directly by crossing into his territory by the River Thames at its only fordable point. Cassivellaunus had clearly anticipated this move, because the opposite bank was not only defended, but it had also been fortified with sharpened stakes driven into the riverbank, and others concealed beneath the water. Again, the improvement of a natural defensive position in this way is not a concept that we generally associate with the Britons. Although Caesar took the time to describe these perils, he oddly makes no mention of them having impeded his attack. Remarkably, considering the threat that they would have posed to cavalry, he sent the Gauls across first with the idea of the infantry, up to their necks in water, getting over to support them as quickly as they were able. In the event the infantry moved so fast that they were able to deliver their attack at the same moment as the cavalry, pushing the Britons clear of the bank. It is hard to imagine how the Romans could have fought them off so casually, given the depth of the river and the snares that had been laid in their path, particularly considering the dire difficulties that they had experienced, in probably similar circumstances, as they waded ashore on the first invasion. Either the defences were not as elaborate as Caesar would have his audience believe, or else the fighting must have been a far grimmer affair as man and beast struggled to thread their way through the nest of stakes while the unencumbered Britons fell upon them.
Cassivellaunus did not attempt any more pitched battles after this stand on the Thames. Instead he took the decision to disband the greater part of his army, who, with no battle to fight, became only an administrative responsibility and unwanted mouths to feed. Although he had given up hope of defeating the legions in a direct confrontation, Cassivellaunus continued to wage a guerilla war using the 4,000 charioteers that he had kept about him. These warriors, judging by Caesar's earlier descriptions of them, were highly mobile and as skilled in fighting on the move as they were on foot. They were, therefore, ideal for a hit and run campaign.
The Romans advanced into his territory and laid waste to it, plundering and burning as they went. Cassivellaunus made no attempt to interfere with the main column of infantry as they advanced, but, Caesar writes: "... he watched our line of march. He would retire a short way from the route and hide in dense thickets, driving the inhabitants and cattle from the open country into the woods wherever he knew we intended to pass. If ever our cavalry incautiously ventured too far away in plundering and devastating the country, he would send all his charioteers out of the woods by well-known lanes and pathways and deliver very formidable attacks, hoping by this means to make them afraid to go far afield." And in this he succeeded, because Caesar goes on to say that he was compelled to keep the cavalry in much closer contact with his slow-moving and tired infantry, consequently the Britons were somewhat let off the hook.
We might go further and say that Cassivellaunus had won something of a victory here, utterly blunting Caesar's strategy. The tactic of laying waste to the land is traditionally used to force a reluctant enemy to offer battle, which would not have happened in this case, but it could also be used to undermine Cassivellaunus' power to such a degree that he would be compelled to seek peace on terms that were very favourable to Rome. Most of the devastation appears to have been carried out by the Gallic cavalry, whose mobility enabled them to range far and wide, and, most importantly of all, descend on settlements before an alarm could be sounded. They were an essential part of this strategy, and so they must have suffered very heavily in the ambushes if Caesar had to call them off. Through being forced to keep the cavalry within range of infantry support, a severe curb was placed on Caesar's plans; he clearly states that the Britons, by stalking the legions, were able to gauge their destination and could remove anything of value from their path; settlements evacuated of both people and livestock, maybe all their possessions too if there was time. We can, therefore, deduce that Cassivellaunus, far from being brought before Caesar on his knees, had forced a stalemate upon him; he could not defeat Caesar, but Caesar could not defeat him. By being denied the luxury of having his cavalry venture in all directions to unleash their sudden attacks, Caesar now found himself pointlessly plodding through hostile country like a dog chasing his own tail.
His campaign of devastation frustrated, Caesar simply changed tack and began a war of diplomacy. The Trinovantes, a tribe in the south-east of Britain, referred to by Caesar as being the strongest in the region, although we must then wonder how Cassivellaunus had previously put them at such a disadvantage if this were so, sent a delegation to him to offer their surrender. This tribe had reason to hate Cassivellaunus; it is said that he had killed their king, and his son, Mandubracius had fled to the continent to seek Roman protection. Having thus yielded, the Trinovantes pledged to submit to Roman instruction and asked, in return, that Mandubracius was restored to the throne. Caesar agreed and imposed trivial terms; 40 hostages and a supply of grain for his troops. These were duly provided and so the Trinovantes escaped Cassivellaunus' grip. Having seen how lightly the Trinovantes had been treated, other tribes abandoned the alliance and sought to make their peace with Rome; Caesar names the Cenimagni, Segontiaci, Ancalites, Bibroci, and Cassi as having done so. Here we see the traditional Roman tactic of divide and conquer; exploiting tribal hatreds to make peace with one group and then standing united against a common foe. Cassivellaunus was at a disadvantage in his attempts to resist these defections; having spent some years trying to assert his dominance over his neighbours, we can assume that he had few friends.
Rome's new allies informed Caesar of the location of Cassivellaunus' own stronghold, possibly near modern Wheathampstead and not Verulamium as has been previously thought. He writes that it was "protected by forests and marshes and had been filled with a large number of men and cattle... He [Caesar] marched to the place with his legions, and found that it was of great natural strength and excellently fortified. Nevertheless, he proceeded to assault it on two sides. After a short time the enemy proved unable to resist the violent attack of the legions and rushed out of the fortress on another side. A quantity of cattle was found there, and many of the fugitives were captured or killed." Once again we see how vulnerable hill forts are to Roman organisation. How seriously it was defended is open to question; Cassivellaunus and his elite charioteers were probably still tracking the legions, but there is no mention of their having intervened. The loss of his fort was of little strategic importance, although it most likely played havoc with his prestige.
Cassivellaunus had a last throw of the dice and encouraged the four tribes in the Kent region to attack the Roman fleet; if they destroyed it then, without question, Caesar's offensive would be over. The attack came to nothing: "When these forces appeared the Romans made a sortie, in which without suffering any loss they killed a great many of them and captured Lugotorix, a leader of noble birth." We may question the authenticity of this summary of the battle, for however ill-conceived the British attack may have been, it is scarcely credible that a force, which must have been of a considerable size to pose a threat to the ten cohorts placed in defence of the camp, could be put to flight without a single Roman casualty. But such statistics count for little, for the Romans had withstood every enterprise that the Britons had thrown at them, and they now had mastery of the south-east.
Cassivellaunus recognised this too, and so, employing an ambassador in the form of Commius, the Gaul and later king of the British Atrebates, who had been attached to Caesar's entourage since the first invasion, he sought terms for an armistice. Rome demanded an unspecified number of hostages and annual tribute, to be collected from all the tribes, and Cassivellaunus was told to respect the independence of the Trinovantes. Throughout his career, Caesar was notoriously lenient in the aftermath of his victories, so it is of small surprise that Cassivellaunus was allowed to keep his kingdom and the reparations were not, one imagines, particularly exacting. A further justification is mentioned in his text which implies that Cassivellaunus, however eager to end the conflict, was not in such peril that he could not continue the fight if harsh terms compelled him to do so; winter was approaching and "the Britons could easily hold out for the short time that remained." Whether the terms survived Caesar's stay in Britain is not known; hostages were delivered to him before he set sail for Gaul, but the annual tribute was most likely forgotten at the earliest opportunity.
Had Caesar been victorious? If his intention had been, as he had stated, a campaign to force the Britons to respect Rome, then he most certainly had. If, as is suspected, he hoped to create a Roman province in the south-east of Britain, then it was a failure. The war may have ended with Rome dominating this region, but it is impossible to accurately assess from amongst the propaganda just how firm was their grip; we can surmise that the tribes had not suddenly become fiercely proud subjects of Rome and would remain so, most likely they would revolt at the very first opportunity and Caesar knew it.
For a province to take shape, Caesar would have had to maintain a presence in Britain. He did not do this, instead the entire army returned to Gaul forthwith. Why did he leave? The hostility of the tribes was one factor, waiting for the opportunity to cast off their shackles the very moment that circumstances placed their jailer at a disadvantage. Also Cassivellaunus had not been defeated outright, and if his hit and run tactics were repeated during a rebellion then the legions could be put under severe pressure. There is also the possibility that if Caesar had been motivated by plunder, as Roman commentators themselves suggested, then the discovery that there was no great gold wealth in Britain simply invalidated the purpose of the entire campaign. The most significant stimulus though lay across the Channel; Gaul was ripening for revolt. Caesar voiced his concerns on this issue repeatedly, and with good reason, because large parts of the country were in rebellion before the summer was out, and would remain so for several years. We can conclude, therefore, that whatever other ambitions Caesar may have had in Britain, a presence there was quite impossible while there was widespread unrest in Gaul.