Roman Military Campaigns – Gaius Julius Caesar (55 -54 BC)

We are provided with a commentary of Caesar’s British campaigns in his own memoirs; De Bello Gallico (book IV, chapters 20-38) which describes his first expedition in 55 BC and (book V, chapters 1-23) his second campaign the following year. Anyone wishing to understand the background for Caesar’s British campaigns should perhaps start by reading Caesar’s own commentaries. What follows is RBO‘s own interpretation of the events described by Caesar with a discussion on the archaeological evidence for his campaigns in the British Isles.

The Campaign of 55 BC

As a prelude to his first expedition to Britain Caesar sent his friend, ally and former adversary Commius the Gaul, the King of the Gallic Atrebates tribe, across the English Channel to try to persuade the British tribes to submit to Caesar’s terms without forcing him to do battle. At the same time, however, he sent his trusted lieutenant Gaius Volusenus Quadratus, the commander of his cavalry during many of his gallic campaigns, in a fast trireme to scout suitable landing-places along the British coast. Volusenus returned after five days reconnaissance and submitted his report. The following day, having heard no word from his Atrebatean ambassador, Caesar’s invasion fleet left Gesoriacum (Boulogne-sur-Mer) on the evening tide and set sail for Britain.

For his first adventure beyond Oceanus Caesar’s fleet comprised some eighty ships, mostly requisitioned from the Veneti and other maritime Gallic tribes conquered in the preceeding campaigns throughout Gaul. Besides a few specially-built triremes and a number of slower but more manoeverable libernae or war-biremes, the majority were sea-going, estuarine or even large riverine vessels, monoremed actuaria or merchant galleys, flat-bottomed barcae and high-keeled scaphae of a number of different shapes and sizes. Upon this motley collection of vessels Caesar had embarked two of his most highly-trained legions, Legio VII and Legio X, numbering in excess of ten-thousand seasoned veteran troops.

Caesar had also made provision for tranporting a substantial cavalry contingent for use during his initial assault on Britain, who were directed to another small port at Ambleteuse a little further along the Gallic coast where another eighteen riverine barges awaited their arrival. The number of auxiliary cavalry units which comprised this expeditionary force is not recorded by Caesar and modern estimates range from a single ala to three or even four alae, that is, between five-hundred to two-thousand men and horses. Whatever its size, the cavalry contingent, presumably under the command of Volusenus, suffered a substantial delay during embarkation of their horses and as a consequence missed the evening tide. The transports carrying the cavalry finally sailed on the morning tide but even then they were forced to turn back due to adverse weather conditions. Caesar’s first expedition to Britain would be without Cavalry back-up.

25th August 55 BC in a trireme off the coast of Cantium … about 9 AM

Julius Caesar had observed the British army and thier war-chariots massing on the white chalk cliffs above the safe harbour at Dubris as his fleet approached the British coast. Seeing this hostile reception committee and being aware that he needed horses to keep the British chariots at bay, he kept his entire invasion force waiting at anchor off the coast of Cantium until the remaining eighteen transport vessels carrying his auxiliary Cavalry arrived. He waited for over six hours.

Finally, at half-three in the afternoon with still no sign of his cavalry but with both wind and tide favourable, Caesar ordered his fleet to weigh anchor. The triremes, biremes and monoremes of the Roman invasion force then proceeded along the coast to the north-east, some of the larger ships towing smaller unpowered vessels behind them, shadowed all the while on land by the charioteers and foot-soldiers of the gathered British tribes. For ‘about seven miles’ Caesar guided his ships until he came to the gently shelving shingle beaches between Walmer and Deal.

At first the sight of the British chariots charging up and down the beach – which the Romans had never before experienced in warfare – dissuaded Caesar’s troops from disembarking and joining battle. With their general being offshore aboard his trireme and unable to effect the morale of his troops in the initial landing force, it took the actions of a single unnamed soldier to turn the tide of battle. Seeing the invasion losing momentum, the standard bearer of Caesar’s Tenth Legion leaped overboard into the Cantium shallows shouting.

  • ‘Leap, fellow soldiers, unless you wish to betray your eagle to the enemy. I, for my part, will perform my duty to the commonwealth and my general.’ (Caesar, De Bello Gallico, IV.xxv)

With these words he waded forward carrying the legionary standard toward the waiting British. These actions prompted his fellow legionaries almost as a single entity to surge forward off the transport vessels and into the waves, choosing to follow the legionary standard into battle rather than suffer the shame and ignominy of allowing their revered holy symbol fall into enemy hands. (see Roman Standards).

Anyone interested in the nitty-gritty details of Caesar’s first campaign in Britain should acquaint themseves with his own words in The Gallic Wars (book IV, chapters 20-38). To cut a long story short, the battle on the beaches between Deal and Walmer was won by the experience and discipline of Caesar’s Roman legionaries, who put the British army to flight soon after they had gained a foothold on dry land.

Caesar First Encounters the British Weather

For the next few day Caesar was content to consolidate his bridgehead encampment and to receive the embassies of the British tribes, who now sued for peace with promises of hostages and tribute, also returning his own ambassador Commius the Gaul, whom they had kept imprisoned. On the morning of his fourth day in Britain, the eighteen ships carrying Caesar’s cavalry finally came into view of his encampment. Then things started going badly wrong for the Roman general. Just as the cavalry transports neared the British coast a squall blew up out of nowhere and threatened to dash the ships to pieces. The cavalry transports, which were so close to disembarking their cargoes of men and beasts, were forced back across the English Channel; miraculously all of them survived to make landfall back in Gaul. Luckily, the triremes and liburnae of Caesars fleet had been hauled ashore sometime before the weather turned, leaving the merchant galleys and transport vessels at anchor just offshore to bear the brunt of the storm’s ferocity.

The storm raged for the next few days, during which the Britons, seeing Caesar’s fleet being battered to pieces off the Kentish coast, took renewed courage from the Roman general’s misfortune and launched an ambush upon the Seventh Legion while it was foraging for food. Upon hearing of this British volte-face, Caesar mobilised the remainder of his troops and, leaving behind only a small reserve force to hold the bridgehead fortifications, he dealt the British forces a resounding defeat and managed to retreat with the majority of his army still intact, back to the relative safety of his encampment. Following this last encounter with the British army the storm abated and Caesar managed to effect repairs to all but twelve of his ships. With this accomplished, at nightfall he and his invasion army boarded thier transports and departed Cantium, returning to the continent.

The Campaign of 54 BC

While Caesar spent the winter of 55/54 BC in Rome he had left orders with his legionary legates encamped in northern Gaul to build him a fleet of ships to his own specification, specially designed for the transport of men and horses. When he returned to Gaul the following Spring, Caesar found six-hundred new transport vessels of his new design along with twenty-eight new triremes awaiting him at various places on the Gaulish coast closest to Britain. After ordering his fleet be assembled at Portus Itius, Caesar was first obliged to put down an uprising of the Treviri tribe of the Ardennes, then of the Aedui tribe in the Auxerre region of central France, which he accomplished with the aid of four legions, eight-hundred cavalry and his own peculiar brand of diplomacy and gangsterism.

Things set right on the continent, Caesar then loaded his transports with five legions and two-thousand auxiliary cavalry troopers, along with a considerable number of hostages taken from amongst the Gaulish nobility. Leaving behind three legions and two-thousand horse to secure his rear, under the command of his legate Titus Labienus, Caesar’s fleet, numbering in excess of eight-hundred vessels, set sail from Portus Itius at sunset and arrived off the shores of Cantium the following mid-day. This time his landing on the beaches between Walmer and Deal was unopposed. The British host which had originally gathered to repulse him having once sighted his mighty invasion fleet evidently decided that ‘the better part of valour is discretion’¹ and melted away into the Kentish countryside, allowing Caesar to establish his bridgehead without hinderance.

  1. Falstaff, from Will Shakespeare’s Henry IV : Part I – a bit anachronistic, I know, but still a valid axiom.

Immediately after establishing a foothold on the British coast Caesar headed inland, leaving behind ten legionary cohorts and three-hundred cavalry troopers under the command of his legate Quintus Atrius to secure his rear. It is evident from his wording that this rearguard did not comprise a single legion, as he would have simply named the unit in question, instead he states that ‘ten cohorts’ were left behind, implying that they had been drawn from several – perhaps all five – of the legions he had at hand.

The bridgehead encampment built by Caesar’s rear-guard must have been of a size sufficient to house at least five-thousand men (and three hundred horses) in field conditions and would have required a defensive enclosure of at least 25 acres (c.10 ha). Nothing of this camp has been found by modern archaeology but most modern scholars are convinced that it must have been situated somewhere in the area of Walmer and Deal.

The Battle at the River and the Fall of the British Camp

Leaving the bridgehead, Caesar and his army, comprising five slightly under-strength legions and seventeen hundred horse, advanced by night a distance of about twelve miles until, at dawn, British warriors, horses and chariots were sighted upon the high ground on the opposite bank of a river – unnamed by Caesar but almost certainly the Great Stour. While crossing the river Caesar’s army was hindered by repeated charges from the British chariots and mounted warriors, but once his own cavalry had safely forded they were at once put to work against the opposing mobile forces, soon causing the horses and chariots to withdraw from the field of battle into the surrounding heavily-wooded countryside. Without the support of cavalry the British infantry were no match for their Roman legionary counterparts and quickly retreated into prepared positions on the west bank of the river.

This defended British position, described by Caesar as ‘a place admirably fortified by nature and by the artifice of man,’ was seen by him to be the product of earlier ‘civil wars’ among the indigenous Kentish tribes and was evidently uninhabited at the time of his encounter. These extant earthworks had been further strengthened by having all entrances blocked with tree-trunks. Caesar set a single one of his legions, the Seventh, to the task of reducing the fortifications, perhaps in order to indulge their taste for vengeance after having been mauled by British forces whilst foraging in Cantium during the previous campaign season.

The hastily improvised entrenchments were to prove no match for the Roman antagonists. The Seventh Legion assumed the famous testudo or ‘tortoise’ formation, with shields held aloft, to the fore and at the sides, making it almost invulnerable to attack. Under the cover of this defensive armour-plating the legionaries created a causeway and ramp across the defensive ditch and rampart of the British camp, thereby breaching its defences and overrunning the interior. The defenders were quickly overwhelmed and those who were given the opportunity fled into the surrounding woods, but Caesar forbade any of his own forces from pursuit as it was approaching nightfall and he ‘wished time to be left for the fortification of the camp.’ We must also bear in mind that his men had not yet been afforded any time to rest since leaving Gaul.

The hillfort of the Cantiaci is not named by Caesar, probably because it was uninhabited at the time of his campaigns and, being described by him as situated within woodland, it had probably been uninhabited for a reasonable period prior to his arrival. Guided by the narrative of Caesar but unconfirmed by any archaeological evidence, modern scholars have identified the Iron-Age hillfort at Bigbury, directly west of Canterbury on the opposite bank of the Great Stour, as the site of the Seventh Legion’s victory in Cantium.

Caesar Falls Foul of the British Weather … Again!

Early the next morning Caesar sent out a number of separate forces, presumably upon different trajectories, to reconnoitre the Kentish countryside and to seek out the British forces, while the general himself remained at the field encampment with the remainder of his army. The exact size and composition of these expeditionary forces is not given in Caesar’s commentaries (GW, V.x-xi), which merely records that ‘tripertito milites equitesque,’ or three divisions of both infantry and cavalry were despatched, but he later reports that ‘legiones equitatumque revocari‘, his legions and cavalry were recalled, which implies that each division had a legion at its core. The cavalry contingent which accompanied these three expeditionary divisions cannot be known with any certainty but was probably in the region of three to four-hundred troopers. Caesar thus retained about five to eight-hundred cavalry and the better part of two legions at his base camp, one of these legions probably being the Seventh, who had borne the brunt of the fighting the previous day.

At the same moment that the first of these expeditionary forces had made contact with the rearmost stragglers of the fleeing British host Caesar received news from Quintus Atrius at the bridgehead encampment which caused him to order the immediate cessation of pursuit and to recall all three scouting divisions back to camp. Whilst Caesar had been encamped on the night of the battle a serious storm had struck the Straits of Dover and wrecked almost his entire fleet, many vessels of which had been at anchor when the storm struck and had been driven upon the shingle beaches. Leaving his field-encampment and returning to the beach-head, Caesar found that forty ships had been completely destroyed, while the others, in varying states of repair, could with some considerable effort be made seaworthy once more.

To ensure the safety of his men Caesar ordered that while repairs were being undertaken every vessel in his fleet should be brought ashore within a single large fortification which was to include the beach-head encampment within its perimeter. Word was sent to the reserve force in Gaul to supply engineers and the necessary ship-building materials, also orders for his legates there to build him more vessels to his recent specifications and to send them to Britain. To effect these ‘strong fortifications’ and to undertake the necessary repairs to his fleet took ten days, working day and night, before Caesar was satisfied that he could return to his task of bringing the Britons to battle. Ten days during which the British tribes could muster a significant response to his invasion army. He had lost the initiative and this was to have serious consequences with his long-term plans.

Physical evidence for Caesar’s shipyard extension to his bridgehead fortifications, which must have been of some considerable size, has never been found in the area of Walmer and Deal. In fact, there is absolutely no evidence at all, for any of the furious boat-building activities which must have been undertaken on the Kentish beaches – and we should expect little. It is very likely that Caesar had no idea of the large supplies of iron-ore which were available nearby in the Weald of Sussex, and even if he did, his forces were not in a position to obtain these raw materials without exposing himself to other dangers. Caesar’s experiences in Britain the previous year had probably prompted him to carry a sufficient quantity of iron nails to enable him to effect most of the repairs, and he could quite easily have had extra supplies sent over from the continent along with the legionary engineers which he is known to have requested from his legate Labienus at Portus Itius. Given this, we are not likely to find any iron-smelting sites attributable to Caesar, and all the other shipyard activities, such as the felling and transport of timber, the shaping of the wood and the fixing of sails and rigging will leave little or no evidence after the passing of two millenia. The absolute lack of any evidence for the bridgehead fortifications is, however, most perplexing to later antiquarians and modern archaeologists alike.

The Advance Through Cantium and the Battle at the Camp

After ten days then, Caesar returned to his field-encampment and quickly found that the British had re-appeared on the scene in greater numbers than before. The forces of the British, visible from the Roman camp, this time consisted not only of the various peoples from the four corners of Cantium, but also of the combined tribes from the entire south-east of England. This army was placed under the overall command of the warlord Cassivellaunus whose own lands were bordered to the south by the Thames; his people later became known to Rome as the Catuvellauni, perhaps named after this spirited leader. Despite the presence of the British army, Caesar advanced his forces westwards through Kent but the british did not give battle and retreated before him. Caesar does not give the dispositions of his mobile army, but it is possible that it operated in the same manner as described before, with three legionary divisions supported by cavalry stationed in the vanguard and upon the flanks while he rode at the center with two legions and the rest of the cavalry. The only military actions during this advance were, apparently, mere skirmishes between Caesar’s screening cavalry and the British chariots, the Roman auxiliaries consistently proving themselves the better of the two opponents.

Only when Caesar’s forces had stopped to make another field encampment somewhere in west Kent were the British infantry finally brought into action. While the camp ditch was being dug and the rampart erected, the British warriors emerged from the Kentish countryside and threw themselves upon the Roman defensive pickets. These were quickly reinforced by the first (double strength) cohorts from two of Caesar’s legions who apparently tried to envelop the British forces in a ‘pincer’ movement, but the native tribesmen managed to withdraw through the narrowing gap before the manoever could be completed and melted back into the gathering darkness. It is not known whether Cassivellaunus himself commanded the force which attacked Caesar’s second field camp, but the fact that their commander not only realised the danger but was also able to effect an escape proves at the very least that this was a competently led force. The British assault on the camp was not without success, however, for one of Caesar’s military tribunes, Quintus Laberius Durus by name, was killed in the attack.

As already mentioned, Caesar’s Commentaries contain very little detail of his advance through Kent, mentioning neither the disposition of his forces nor the topography through which they moved. Caesar twice mentions the Thames, however, no mention is made of his forces actually sighting this river, nor any other prior to his report of the attack on his camp. This leads me to believe that his second field encampment where he was set upon by the forces of Cassivellaunus lay somewhere east of the Medway, possibly in the area between Maidstone and Chatham. My own hunch/guess/deduction is that the camp lies upon the line of the North Downs Way somewhere in the area of Burham Common, perhaps at Burham Hill Farm or at Keeper’s Lodge on nearby Wouldham Common. There is no archaeological evidence, however, to support this assumption. There are a number of scattered Roman pottery finds in the area, but this medium is hardly in keeping with an army operating under field conditions as pottery was prone to breakage, also Roman coin finds, including solitary finds and hoards, are all dated to the later Roman occupation period.

Further Battles in Kent and at the Flumen Tamesin

The following morning the British forces were visible upon the hilltops before the Roman camp, prompting Caesar to send out his cavalry to test their strength. The cavalry were harrassed only by a number of small raiding parties which were easily repulsed, so three legions were sent out under the overall command of the legate Gaius Trebonius to look for supplies. While engaged in foraging, these legions were protected by a defensive screen comprising all of Caesar’s available cavalry, numbering seventeen-hundred troopers. Suddenly, from many directions, the British charged upon the dispersed legionaries, in some places breaking through the cavalry cordon and bringing the legions themselves to battle, to the point even, of threatening the Roman standards. The legionaries were soon rallied under Trebonius and the attack was soundly repulsed with many British falling beneath the short, stabbing gladius of the Roman legionary and many more succumbing to the long, slashing spatha of the mounted auxiliaries, as the natives fled from the scene in disarray.

Following up on this success and in response to intelligence reports concerning the whereabouts of the British warlord Cassivellaunus, Caesar immediately marched his entire mobile army to a ford across the River Thames where he found the British host waiting upon the opposite bank. The natives had fortified the north side of the river-crossing by an intermittent palisade from which they taunted the Romans, daring them to cross the river and fight, confident in the knowledge that they had placed a great many sharpened stakes in the riverbed, hidden beneath the waterline, upon which they expected to entrap any advancing enemy. Caesar had already learned of these defences from disaffected British captives, so, forewarned and lusting for battle, his legions crossed the river at the same time as his cavalry, easily avoiding the underwater obstacles and falling upon the surprised defenders. The combined British army of Cassivellaunus was smashed to pieces on the north bank of the Thames, the separate tribal contingents each departing the battlefield by the most expedient routes to return homeward. All except the British overlord himself, shorn of the peregrine mass of his army, who alone confronted the invaders from within the borders of his homelands, harrassing them by continual guerilla-like raids assisted by a highly mobile force of four-thousand loyal charioteers.

My studies regarding the site of Caesar’s second marching camp in Kent (see above) places this encampment somewhere upon the ridge of the North Downs Way overlooking Burham. Given this, it would follow that the scene of the battle between his foraging legions and the ambushing British forces would have been somewhere on the flood plain of the Medway’s east bank, possibly in the area between Eccles and Aylesford. Aside from the well known Romano-British villa just west of Eccles itself, there are plenty of LPRIA, ‘Belgic’ and Romano-British archaeological sites known and recorded in this area, as well as a number of scattered finds, as one might expect in that part of Britain lying closest to the Romanising influences of the continent. Despite the profusion of remains from the time period, there are none which may be positively attributed to Caesar’s battles in Kent. There are, however, two sites of particular interest; a ‘Late iron-age Urnfield’ containing many cremation burials which was excavated by A.J. Evans in 1886 in an old sand quarry about 200 yards (c.183 m) north-east of the church at Aylesford (TQ 7309 5924; Archaeologia Vol.LII, 1890/2, pp.315-388), also another cemetery containing ‘many Roman burials’ which was found (c.1893) at Burham ‘near the road towards Eccles’ (VCH Kent vol.III, 1932, pp.149, 153).

Concerning the scene of Caesar’s crossing of the Thames where his forces circumvented the underwater obstacles prepared by the British, it is possible that this occurred at Brentford, upstream along the Thames from the site of the later Roman capital. A number of piles driven into the river-bed and foreshore on the north side of the river here may possibly be dated to the Late Pre-Roman Iron-Age, and a number of bronze-, iron-age and Roman weapons and artefacts dredged from the area are now on display in the London Museum and the British Museum. These unconnected finds cannot be taken as evidence for the actual site of Caesar’s forced crossing; it is more likely that these piles represent the remains of a pier or landing-stage to allow larger vessels to unload cargoes ashore or onto smaller vessels for further riverine transport upstream, the artefacts may be due to accidental deposition during normal dockside activities (TQ 1792 7704; EHNMR-397917). It may be significant, however, that Brentford is known to be the site of two battles in later times, both of which were fought on the north bank of the Thames in the area of Syon Park (TQ 1760 7680; OS):

  • 1016 – Following the death of King Aethelred there were two contenders for the throne of England, Edmund Ironside and Knut the Dane. Two days after Edmund had repulsed Viking longships from London, he crossed the river at Brentford with his army and put the forces of Knut to flight, despite having lost some of his troops who tried to cross the Thames further downstream in a flanking movement.
  • November 12th 1642 – During the English Civil War Prince Rupert commanding the King’s Welsh Regiment defeated and routed two regiments of Parliamentary infantry under the command of Colonel Holles who had been detailed to hold the crossing, the Royalist forces then held the crossing, expending all of their powder and shot, until the rest of the King’s army arrived and drove off the Parliamentarians.

The Fall of Cassivellaunus Fortress and his Capitulation

Cassivellaunus was a historical British military leader who led the defence against Julius Caesar’s second expedition to Britain in 54 BC. He led an alliance of tribes against Roman forces, but eventually surrendered after his location was revealed to Julius Caesar by defeated Britons.

Evidence for Caesar’s Campaigns in Britain

Even though the autobiographical works of Caesar document both of his British campaigns they give very little geographical detail. He mentions no geographical location in Britain by name except Cantium and the River Thames (flumen Tamesin) and none of the other sites he describes may be positively identified. Even though he mentions the construction of several encampments on British soil no archaeological evidence of these fortifications has ever been found, indeed, we have nothing which can be conclusively attributed to either of Caesar’s expeditions.

It is perhaps noteworthy that Caesar’s autobiography states that during his second campaign, upon disembarking his troops he then looked for a place to encamp, implying that the fortifications he had established during his last excursion were no longer standing. These bridgehead fortifications built the previous campaign season may have been demolished by the people of Cantium, but it is much more likely that Caesar had himself ordered their demolition prior to departing Britain in 55 BC, to prevent them being used by the British to oppose his planned return to the island. This would have made sound military sense and it is very likely that Caesar demolished his substantial bridgehead fortifications of the following year before leaving Britain for the same reason, because it is evident from his autobiographies that he intended to revisit the island but was prevented from doing so by continued unrest amongst the tribes in Gaul and later by political machinations at Rome.

Evidence from the Continent

Even on the continent nothing of the preparations for Caesar’s British expeditions have been positively identified. The embarkation port for the first campaign is not mentioned by name but is assumed to have been Gesoriacum / Bononia (Boulogne-sur-Mer), but no Roman camps or buildings have been found here which may be dated to Caesar’s time. The point of departure for the second campaign is actually named as Portus Itius but this harbour has never been positively identified.

T. Rice Holmes in 1909 made a very good argument for Portus Itius being Wissant, about four miles east of Cap Gris-Nez, which was itself named Promonturium Itium by Ptolemy. Wissant has very little evidence for Roman occupation at any time, but there is an undoubtedly ancient camp lying in fields to the east of the modern village referred to locally as ‘Le Fort César’. This is, however, very wishful thinking, as the site in question is ovular in outline and measures roughly 88 x 53 m (c.289 x 174 feet), enclosing an area of only 0.4 hectares (just over one acre), which is hardly big enough to have housed a single cohort, let alone the three legions and two-thousand horse that are known to have been left behind at Portus Itius in 54 BC.


  • The Roman Invasion of Britain by Graham Webster (Batsford, London, 1980);
  • Rome Against Caratacus by Graham Webster (Batsford, London, 1981);
  • Britons and the Roman Army by Grace Simpson (Gregg, London, 1964);
  • Historical Map and Guide: Roman Britain by the OS (3rd Edition, 1956; 4th Ed., 1990; 5th Ed., 2001);
  • The History and Topographical Survey of the County of Kent: Volume 1 – From British History Online
  • A History of the County of Middlesex: Volume 1 – From British History Online The Council for Kentish Archaeology – Publishers of Kent Archaeological Review