The Romans first invaded Britain in 55 and 54 BCE under Julius Caesar, but the full conquest began in AD 43 under Emperor Claudius.

Quick Scoop: Key Dates

  • 55 BCE – Julius Caesar leads the first Roman expedition to Britain; it is more of a show of strength than a lasting conquest.
  • 54 BCE – Caesar returns with a larger force, wins battles, takes hostages and tribute, but again does not stay to rule Britain.
  • AD 43 – Emperor Claudius launches a major, permanent invasion, sending four legions to conquer and occupy southern Britain; this is what historians usually mean by “the Roman invasion of Britain.”

So, if your question is “when did the Romans invade Britain?” in the sense of permanent conquest, the usual answer is AD 43 ; if you include the earliest landings, then 55 BCE is the first Roman invasion attempt.