The Romans invaded Britain in earnest in AD 43 under the Roman Emperor Claudius. This marked the beginning of the Roman conquest of most of the island, which was carried out over the following decades, mainly in the southern half of Britain (modern-day England and Wales). The conquered territory became the Roman province of Britannia.
Before this full invasion, Julius Caesar had conducted two military expeditions to Britain in 55 and 54 BC. These were not full-scale invasions aimed at conquest but rather exploratory and punitive expeditions that resulted in some British tribes becoming allies or tributaries of Rome. However, lasting Roman control began only with Claudius's invasion in AD 43.
