The military campaigns of Julius Caesar constituted both the Gallic War (58 BC–51 BC) and Caesar's civil war (50 BC–45 BC). The Gallic War mainly took place in what is now France. In 55 and 54 BC, he invaded Britain, although he made little headway. The Gallic War ended with complete Roman victory at the Battle of Alesia. This was followed by the civil war, during which time Caesar chased his rivals to Greece, decisively defeating them there. He then went to Egypt, where he defeated the Egyptian pharaoh and put Cleopatra on the throne. He then finished off his Roman opponents in Africa and Hispania. Once his campaigns were over, he served as Roman dictator until his assassination on March 15, 44 BC. These wars were critically important in the transition of the Roman Republic into the Roman