The Battle of the Medway took place in 43 on the River Medway in the lands of the Iron Age  tribe of the Cantiaci, now the English county of Kent. It was an early battle in the Claudian invasion of Britain, led by Aulus Plautius.
On the news of the Roman landing, the British tribes united under the command of Togodumnus and his brother Caratacus of the Catuvellauni tribe to fight them. After losing two initial skirmishes in eastern Kent, the natives gathered on the banks of a river further west to face the invaders.
At the same time, the Romans received the surrender of the Dobunni tribe in western Britain. The Dobunni were subjects of the Catuvellauni and this diplomatic gain was likely a blow to native morale and manpower.
There was no bridge over the river and so a detachment of specially-trained Roman auxiliaries (described by the only historical source for the battle Cassius Dio as "Celtic") swam across the river and attacked the natives' chariot horses. In the chaos that followed, the bulk of the invasion force spearheaded by Legio II Augusta under Vespasian crossed the river, under the overall command of Titus Flavius Sabinus II. It seems the natives were taken by surprise at how fully armed legionaries were able to cross the river and Peter Salway states that even Dio seems taken aback. The Romans were unable to press home victory immediately and the first day of fighting ended without a result. During the second day, a daring attack led by Gnaeus Hosidius Geta almost led to the Roman officer being captured. His troops retaliated however and put the Britons to flight. Geta was awarded a triumph for securing victory, a rare honour for someone who had not been consul. Given the primary roles taken by Geta and Sabinus on different days it has been suggested by the historian Malcolm Todd that the Romans were operating as two, or possibly three, battle groups.
Such a long battle was unusual in ancient warfare and it is likely that the Romans had defeated a significant native force. The Britons fell back to the Thames where they were afforded a greater strategic advantage.
Dio does not in fact name the battle's location or even the river in question but its site is usually said to be on the Medway. The Romans would have made use of existing trackways as they moved west from Richborough, and the most well-travelled prehistoric trackway would have been the route of the later Pilgrims' Way, which forded the Medway at Aylesford. Other theories, however, note that the river is narrow enough at Aylesford not to pose significant difficulties in crossing, and place the battle closer to Rochester, where a large Iron Age settlement stood at the time. Further evidence of a more northern location is at Bredgar, where a find of a hoard of Roman coins from the period has been interpreted as a Roman officer's savings buried for safekeeping before a battle. This hoard could, however, post-date the battle by as much as 20 years. Possibly the Romans followed the future route of Watling Street to the battle, although its role as a pre-Roman communications route is not certain
