Preparation Caesar's approach in the winter of 55–54 BC towards the invasion in 54 BC was far more comprehensive and successful than his initial expedition. New ships had been built over the winter, using experience of Venetic shipbuilding technology being broader and lower for easier beaching, and Caesar now took 800 ships, five legions (instead of two) and 2,000 cavalry. He left the rest of his army in Gaul to keep order. Caesar took with him a good number of Gallic chiefs whom he considered untrustworthy so he could keep an eye on them. This time he named
Portus Itius as the departure point.
Crossing Titus Labienus was left at Portus Itius to oversee regular food transports from there to the British beachhead. The military ships were joined by a flotilla of trading ships captained by Romans and provincials from across the empire, and local Gauls, hoping to cash in on the trading opportunities. It seems more likely that the figure Caesar quotes for the fleet (800 ships) include these traders and the troop-transports, rather than the troop-transports alone. The Roman fleet sailed from France in the evening so that the army could land in daylight. They hoped to use the wind to help cross the Channel, but by midnight the wind dropped and the channel tide carried them too far northeast and at sunrise they saw Britain in the distance on their left. They managed to row and use the reversing tide to arrive at the place identified as the best landing-place the previous year.
Landing Archaeology by the
University of Leicester in 2010 and 2017, taken with Caesar's own description, indicates that the likely landing beach was at
Ebbsfleet in
Pegwell Bay where artefacts and massive earthworks dating from this period have been exposed. The defensive ditch enclosed an area of over , now about 1 km from the sea due to siltation of the former
Wantsum Channel, but in ancient times on a peninsula projecting into the channel. If Caesar had as large a fleet with him as has been suggested, then it is possible that the beaching of ships would have been spread out over a number of miles stretching from Walmer towards Pegwell Bay. The Britons had gathered to oppose the landing but as Caesar states, intimidated by the size of the fleet, withdrew 'and concealed themselves on the high ground' perhaps to give them time to gather their forces. Caesar landed and immediately went to find the Britons' army.
Kent campaign Upon landing, Caesar left
Quintus Atrius in charge of the beach-head with an equivalent of a legion to build and defend the base. He then made an immediate night march inland, where he encountered the British forces at a river crossing, probably somewhere on the
River Stour. The Britons attacked but were repulsed, and attempted to regroup at a fortified place in the forests, possibly the
hillfort at
Bigbury Wood, Kent, but were again defeated and scattered. As it was late in the day and Caesar was unsure of the territory, he called off the pursuit and made camp. However, the next morning, as he prepared to advance further, Caesar received word from Atrius that, once again, his ships at anchor had been dashed against each other in a storm and suffered considerable damage. About forty, he says, were lost. The Romans were unused to Atlantic and
Channel tides and storms, but nevertheless, considering the damage he had sustained the previous year, this was poor planning on Caesar's part. However, Caesar may have exaggerated the number of ships wrecked to magnify his own achievement in rescuing the situation. He returned to the coast, recalling the legions that had gone ahead, and immediately set about repairing his fleet. His men worked day and night for approximately ten days, beaching and repairing the ships, and building a fortified camp around them. Word was sent to Labienus to send more ships. Caesar was on the coast on 1 September, from where he wrote a letter to Cicero. News must have reached Caesar at this point of the death of his daughter
Julia, as Cicero refrained from replying "on account of his mourning".
March inland Caesar then returned to the Stour crossing and found the Britons had massed their forces there.
Cassivellaunus, a warlord from north of the
Thames, had previously been at war with most of the British tribes. He had recently overthrown the king of the powerful
Trinovantes and forced his son,
Mandubracius, into exile. But now, facing invasion, the Britons had appointed Cassivellaunus to lead their combined forces. After several indecisive skirmishes, during which a Roman tribune,
Quintus Laberius Durus, was killed, the Britons attacked a foraging party of three legions under
Gaius Trebonius, but were repulsed and routed by the pursuing Roman cavalry. Cassivellaunus realised he could not defeat Caesar in a
pitched battle. Disbanding the majority of his force and relying on the mobility of his 4,000 chariots and superior knowledge of the terrain, he used
guerrilla tactics to slow the Roman advance. By the time Caesar reached the Thames, the one fordable place available to him had been fortified with sharpened stakes, both on the shore and under the water, and the far bank was defended. Second century sources state that Caesar used a large war elephant, which was equipped with armour and carried archers and slingers in its tower, to put the defenders to flight. When this unknown creature entered the river, the Britons and their horses fled and the Roman army crossed over and entered Cassivellaunus' territory. This may be a confusion with
Claudius's use of elephants during his
conquest of Britain in AD 43. The Trinovantes, whom Caesar describes as the most powerful tribe in the region, and who had recently suffered at Cassivellaunus' hands, sent ambassadors, promising him aid and provisions. Mandubracius, who had accompanied Caesar, was restored as their king, and the Trinovantes provided grain and hostages. Five further tribes, the
Cenimagni,
Segontiaci,
Ancalites,
Bibroci and
Cassi, surrendered to Caesar, and revealed to him the location of Cassivellaunus' stronghold, possibly the hill fort at
Wheathampstead, which he proceeded to put under siege. Cassivellaunus sent word to his allies in Kent,
Cingetorix,
Carvilius,
Taximagulus and
Segovax, described as the "four kings of
Cantium", to stage a diversionary attack on the Roman beach-head to draw Caesar off, but this attack failed, and Cassivellaunus sent ambassadors to negotiate a surrender. Caesar was eager to return to Gaul for the winter due to growing unrest there, and an agreement was mediated by Commius. Cassivellaunus gave hostages, agreed to an annual tribute, and undertook not to make war against Mandubracius or the Trinovantes. Caesar wrote to Cicero on 26 September, confirming the result of the campaign, with hostages but no booty taken, and that his army was about to return to Gaul. He then left, leaving not a single Roman soldier in Britain to enforce his settlement. Whether the tribute was ever paid is unknown. Caesar extracted payment of grain, slaves, and an annual tribute to Rome. However, Britain was not particularly rich at the time;
Marcus Cicero summed up Roman sentiment by saying, "It's also been established that there isn't a scrap of silver in the island and no hope of booty except for slaves and I don't suppose you're expecting them to know much about literature or music!" Regardless, this second trip to Britain was a true invasion, and Caesar achieved his goals. One interpretation is that he had beaten the Britons and extracted tribute; they were now effectively Roman subjects. Caesar was lenient towards the tribes as he needed to leave before the stormy season set in, which would make crossing the channel impossible. However, another interpretation of the details is that Caesar had made a weakly enforced treaty with the Catuvellauni, suggesting that a decisive victory did not occur upon the Britons. Caesar achieving popularity with the Roman peoples, and Cassivellaunus' achievement of the maintained autonomy of the Britons. This is evidenced via the next identifiable king of the Trinovantes, known from
numismatic evidence, was
Addedomarus, who took power c. 20–15 BC, and moved the tribe's capital to Camulodunum. For a brief period c. 10 BC
Tasciovanus of the Catuvellauni issued coins from Camulodunum, suggesting that he conquered the Trinobantes in direct violation of the treaty. ==Aftermath==