Roman Britain (Latin: Britannia or, later, Britanniae, "the Britains") was the area of the island of Great Britain that was governed by the Roman Empire, from AD 43 to 410. Julius Caesar invaded Britain in 55 and 54 BC as part of his Gallic Wars. The Britons had been overrun or culturally assimilated by other Celtic tribes during the British Iron Age and had been aiding Caesar's enemies. He received tribute, installed a friendly king over the Trinovantes, and returned to Gaul. Planned invasions under Augustus were called off in 34, 27, and 25 BC. In AD 40, Caligula assembled 200,000 men at the Channel, only to have them gather seashells. Three years later, Claudius directed four legions to invade Britain and restore an exiled king over the Atrebates. The Romans defeated the Catuvellauni, a