The British Empire was the biggest empire in all history. At its peak it governed a quarter of the world's land and people and dominated all its seas. Though little now remains of the Empire as a political power, its legacy is all around us. It laid the foundation for the global triumph of capitalism. It gave the world its common language, English. It exported both Protestantism and parliaments. And it defeated a succession of rival empires from the Habsburgs' to Hitler's.