Britain is one of the oldest known names for Great Britain, an island off the northwestern coast of continental Europe. It derives from the common Brittonic term "Pritani." The titles Briton and British, which are derived from the same word, apply to its residents as well as, to varied degrees, the smaller islands in its vicinity. The original meaning of Britain was "the whole island," but it came to be used specifically for England after the Romans arrived. Ireland and Scotland were known as separate entities within Britain at that time. England wasn't united until the 12th century when Henry II ruled all four parts of the kingdom with one voice. Before the Romans arrived in England, the area now known as Britain was inhabited by a people called the Celts. They were spread out over what today is France, Ireland, and portions of Germany and Spain. The Celts made their homes in small villages that they tended to be nomadic by nature, moving from place to place looking for better food, security, and opportunities. It's believed they came into contact with the Romans around 200 B.C., who adopted many aspects of Celtic culture including language. After the collapse of the Roman Empire in A.D. 400, the presence of Celts in Britain declined significantly. This was the general name given to the inhabitants of the island of Britannia by the ancient Britons themselves.