In this essay, my primary aims are to examine the reasons, the circumstances and the ways of the conquest of Britannia by the Roman Empire. Julius Caesar, the famous imperator, was the first Roman who stepped on the shore of Britannia. He did not conquer the island but he established a client kingdom there, which can be seen as a preparation for the campaign of Claudius. The Roman Emperor conquered a considerable part of the island in 43 AD. This campaign was followed by several other ones in the next centuries. This essay concentrates mainly on the period from Caesar to the beginning of the third century. I am also interested in why it was important for Rome to conquer a distant island, where rebellious, warrior tribes opposed her. Was Britannia conquered only because of the Roman’s lust for power? Or were other motivations such as military, economical strategy?