Caesar's two invasions of Britain in 55 and 54 BCE constitute the earliest documented Roman contact with the island and the start of Britain's written history.
Key Facts
- First invasion year
- 55 BCE
- Second invasion ships
- 800 ships
- Second invasion legions
- 5 legions
- Second invasion cavalry
- 2,000 cavalry
- First invasion legions
- 2 legions
- Territory conquered
- None; Romans returned to Gaul
By the Numbers
Location
Cause → Event → Consequence
In the course of his Gallic Wars, Julius Caesar sought to extend Roman reach beyond the continent. Britain, largely unknown to Rome and suspected of providing support to Gallic tribes, became a target for military demonstration. Caesar decided to lead expeditions across the Channel to project Roman power and gather intelligence on the island.
Caesar conducted two invasions of Britain: in 55 BCE with two legions, achieving only a coastal landing in Kent; and in 54 BCE with 800 ships, five legions, and 2,000 cavalry. The larger force penetrated into Middlesex, crossed the Thames, and compelled the British warlord Cassivellaunus to pay tribute to Rome, with Mandubracius of the Trinovantes installed as a client king.
Despite military pressure reaching deep into southern Britain, Rome conquered no territory, and the legions withdrew to Gaul. Caesar documented both campaigns in his Commentarii de Bello Gallico, which preserved the earliest significant eyewitness accounts of Britain's people, culture, and geography, effectively inaugurating the written protohistory of Great Britain.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Julius Caesar, Mandubracius (allied with Rome).
Side B
1 belligerent
Cassivellaunus.