The Roman Invasion of AD43

Ernest Black discusses the possible landing sites for the Claudian invasion of Britain in AD 43. While there are good accounts of the other two Roman invasions, controversy still surrounds Claudius’ reasons for invading Britain and his military plans.

TWO Roman invasion fleets left the coast of Gaul. One, sailing from Boulogne, headed for the Thames; the other, starting from the Seine, headed for the Solent. The double invasion, commanded by the Caesar Constantius Chlorus (right) and his praetorian prefect Asclepiodotus, was successful. The year was AD 296. This was the last Roman invasion of Britain; it came following a rebellion, about ten years earlier, and the seizure of power from Rome by Carausius. The defeated defenders of Britain were the troops and mercenaries of Allectus, the rebel ruler in Britain, who had probably killed Carausius, before seizing power from him. Allectus lost his life in a battle with Asclepiodotus’ forces, perhaps somewhere in Hampshire. That it had taken so long for Rome to reassert its authority in Britain was in part due to the difficulty of the Channel crossing, especially when the invaders were faced with a rebel Romano–British army on the other side.

Three hundred and fifty years earlier, Julius Caesar had invaded Britain in two successive summers, landing on the coast of Kent somewhere between Sandwich and Deal. In 55 BC he sailed with two legions from an unnamed port in the territory of the Morini tribe and his cavalry sailed from another unnamed harbour eight Roman miles distant where there were transports that had been unable to reach the designated port because of a contrary wind. It is possible that the main port of departure was Boulogne or Wissant. In 54 BC the port, perhaps the same as that used in the previous year, was Portus Itius which gave a crossing of about 30 Roman miles to Britain. Would that we had so much information about the Claudian invasion in AD 43 which led to the permanent annexation of Britain as a Roman province!

Landing-Places and Commanders
No extant literary source tells us where the invasion army sailed from or where it landed in Britain in AD 43. When the emperor joined his army before the advance on Camulodunum (Colchester), Suetonius tells us that Claudius sailed from Gesoriacum, Boulogne; again, we don’t know where he landed. Cassius Dio states that the invasion force was divided into three ‘so as not to cross as a single force and be hindered in landing somewhere’. This has sometimes been taken to indicate three landings in three separate locations but Dio’s statement is highly suspicious. The validity of the reason given for the alleged division of the army is not self-evident. Dio was writing (in Greek) in the early 3rd century AD and is not noted for taking a critical approach to his sources. One 1st–century historian he used as a source was Cluvius Rufus. Although nothing survives of this man’s work, its character has been plausibly reconstructed by the efforts of ancient historians like G B Townend and T P Wiseman. Cluvius Rufus was more interested in rhetoric than in the practicalities of military operations. Dio seems to have used him in his account of the Boudican Rebellion, in which Dio states that the governor Suetonius Paulinus split his army into three separate divisions before the decisive battle with Boudica’s forces. This division was a Cluvian fiction and is absent from Tacitus’ account of the same event. It was designed to give the general the chance to deliver three separate speeches to the three parts of his army — all duly reproduced by Dio! There is a strong possibility that Dio was also using Cluvius Rufus as a source for the invasion of AD 43. If so, the division of the invasion army into three may simply have been invented by Cluvius Rufus to provide the opportunity for another triad of speeches put into the mouth of Aulus Plautius, commander of Claudius’ invasion force. Perhaps fortunately, Dio did not include these speeches in his account. At any rate, the possibility that the division of Plautius’ army was no more than a literary device makes it inadmissible to use it as an authentic historical fact without good supporting evidence from elsewhere.

Writing in the early 2nd century AD, Suetonius tells us that Claudius sailed from Ostia to Marseilles and was nearly wrecked on the way; he then travelled across Gaul to Boulogne and from there sailed to Britain. Dio tells us that the emperor brought reinforcements including elephants. The emperor’s unfortunate voyage to Marseilles and the accompanying elephants explain why Claudius opted for a short sea-crossing to Britain from Boulogne, probably landing on the coast of Kent. It is clear that it was planned from the beginning that Claudius would come to Britain to gain a personal share in the glory. This makes it likely that earlier in the season at least part of the Roman invasion force had also landed in Kent and established some sort of coastal base that Claudius and his reinforcements could use. It does not necessarily follow that this was the only Roman landing-place in Britain.

One very late (4th century) Roman writer, Eutropius, tells us that there were two commanders of the Roman invasion of Britain in AD 43, Aulus Plautius and Sentius Saturninus. Sentius was a key figure in the manoeuvring that surrounded the coup that brought Claudius to power after the assassination of Caligula in AD 41 and it is not implausible that he held a command in Britain in AD 43. The absence of any mention of him in Dio’s account, where a single army seems to be operating under the command of Plautius, seems to rule this out, however. But can we rely on Dio? Unfortunately, as we have seen, we can’t. If Dio followed a source who concentrated on Plautius’ role in the campaign he may not even have been aware that Sentius took part. That Sentius was present in some capacity is known because he received an award of triumphal insignia for the British campaign — a wax tablet from Pompeii records a contract made in Rome in the Forum of Augustus in front of the triumphal statue of Sentius Saturninus. In his account of the Boudican Rebellion Dio has not a mention of Petilius Cerealis and the IXth Legion, ambushed and defeated by the British rebels. Was Sentius omitted from his account of the events of AD 43
in the same way?

An answer to the question can only be supplied by archaeological evidence and a priori arguments about the most plausible strategy for the invasion. There is archaeological evidence for early Roman military activity at the coastal sites of Richborough in Kent and Fishbourne/Chichester in West Sussex. While the former has traditionally been seen as the landing-place of Aulus Plautius in AD 43, the latter has been associated with the campaign of Vespasian and the IInd Legion into Dorset, probably in AD 44. However, there is no way, short of dendrochronology,
of distinguishing archaeologically between features dating to AD 43 and 44. It would have been feasible for a single Roman invasion force to land in Kent and march to the Thames and then wait for Claudius’ arrival before continuing under his leadership to Camulodunum. It might have made better sense strategically for two forces, landing in Sussex and Kent, to have established control throughout the whole area of Catuvellaunian control south of the Thames, before converging at the river to await Claudius. The two early military roads, Watling Street starting from Richborough, and Stane Street starting from a point in Chichester Harbour south of Dell Quay, converged south of the Thames. These were obviously not built during the campaign of AD 43 but they may indicate the starting-points and meeting-point of two Roman armies taking part in that campaign.

The halt at the Thames is the key element in the Roman strategy. This is where it was planned that Claudius would join his army to lead it against Camulodunum and so establish his claim to military virtus, something he exploited in his propaganda throughout his reign.

By AD 43 the Catuvellaunian hegemony south of the Thames included not only the tribes of Kent but the areas later assigned to the Regni, Atrebates and Belgae, and even, as Dio tells us, the Dobunni. This all had to be sufficiently secure to ensure Claudius’ unimpeded passage through Kent and the triumphal advance north of the Thames. If the tribes outside Kent were not neutralised, this, the pre-eminent objective of the invasion, was put at risk. A landing on the south coast as well as one in Kent would have been a logical move to achieve this.

Timescale
Both Suetonius and Dio reflect an earlier writer who was hostile to Claudius and tried to minimise his role in the invasion, most clearly in the disparaging item that he was only in Britain for 16 days. Yet there may have been a very compelling reason for the brevity of Claudius’ stay. In 54 BC Caesar seems to have intended to take his army to Britain just before mid-June, though his departure was delayed for 25 days by a contrary wind. It seems likely that the invasion of AD 43 was also scheduled for around mid-June. But that didn’t happen. There was a mutiny by the legionaries prior to the embarkation. The mutiny was eventually quelled and the invasion went ahead, but only after an unknown delay. If the Roman forces did not sail until late July or early August then Claudius himself may not have reached the rendezvous at the Thames before early September. He then had to establish his military reputation and leave before the autumn equinox brought on the deterioration of sailing conditions and Claudius risked being stranded in Britain.

Such a scenario would convincingly explain the 16 day limit to Claudius’ stay here, but there is one contradictory piece of evidence. This is a coin minted in Alexandria in Claudius’ third regnal year, that is by 28 August AD 43 at the very latest. It gives Claudius (in Greek) the title Britannicus and Dio tells us that the Senate in Rome awarded him this title, along with the right to celebrate a triumph, when it had received news of his victories in Britain. At face value, then, for news of the victories to have reached the Senate and for news of the award of Britannicus to have reached the mint officials in Alexandria before 28 August Claudius must have been in Britain much earlier, according to Anthony Barrett no later than the beginning of July, and that’s assuming that the coin was minted on the final day of his third regnal year. Unfortunately only a single example of this coin is known at present and it may represent a local mint anticipating the emperor’s victory. Could it have been issued on receipt of the news that the emperor had left Rome on his British expedition? A successful outcome might have seemed like an inevitable consequence to a mint official in Alexandria.

The Campaign
Dio tells us that Plautius first defeated Caratacus, then Togodumnus; he received the surrender of part of the Bodounnoi and left a garrison there; then he fought the Britons at an unnamed river in a two-day battle. The Britons were then defeated in a second river-battle, at the Thames. Shortly after this Togodumnus perished but the Britons’ resistance intensified and so Plautius sent for Claudius and consolidated what he had won south of the Thames. The first river battle has traditionally been located at the Medway, and at the River Arun by J G F Hind, who believes that Plautius landed in Sussex. In the battle at this unnamed river, Dio says that the Keltoi, serving with the Romans, swam across the river and troops under Vespasian and his brother Sabinus got across somehow. On the following day, Hosidius Geta played a decisive part in defeating the Britons after narrowly avoiding capture. At the Thames, specifically at a point where it empties into the Ocean and at flood-tide forms a lake, the Keltoi swam across and other troops crossed by a bridge a little way upstream. In their pursuit of the defeated Britons a number of Roman soldiers were lost in swamps. The first battle is weak on topographical detail and concentrates on named personalities; the second, by contrast, gives a lot of topographical detail but singles out no individuals for mention. Both share an attack by Keltoi swimming across a river and the rest of the army crossing separately at a different location. I have argued that these two battles represent two accounts of the same battle taken from two different sources. One of these, who contributed the battle at the unnamed river, was probably Cluvius Rufus. He provides the grossly inflated figures for the sizes of armies found in Dio’s account of the reigns of Caligula, Claudius and Nero and there is a strong possibility that the two-day battle at the unnamed river is a similar exaggeration. If I am right about this, it would be unwise to accept any of the detail provided about this battle as authentic.

Dio’s account concentrates on the advance of Aulus Plautius’ army. We have seen that one landing-place in AD 43 was almost certainly at Richborough in Kent, though this need not mean that this was the only landing-place or that Plautius’ army was the only Roman army taking part in the invasion. Is there any way of deciding whether or not Plautius advanced through Kent? Dio says that after his initial victories over Caratacus and Togodumnus, Plautius received the surrender of part of the Bodounnoi and left a garrison there before continuing his advance, if I am right, to fight the Britons in only one more battle, at the Thames. It has long been accepted that the name Bodounnoi was a mistake for the Dobunni, a tribe centred in Gloucestershire. Almost certainly, as J G F Hind saw, Plautius’ force must have landed on the coast of Sussex, since access to the Dobunni from here would be possible whereas it would not be for an army advancing through Kent. The Kent invasion may have been led by Sentius Saturninus whose main task will have been to prepare for the arrival of Claudius.