This is the story of some of the most famous and ferocious warriors in history. From the Huns to the Mongols, successive waves of nomadic horsemen swept out of the great steppe lands of central Asia to wreak havoc on the static civilizations of Europe, India and China. How were they so successful? What were the limits of their powers? Professor Hugh Kennedy reveals why such 'undeveloped' societies spawned great generals from Attila to Genghis Khan. He explains how the nomadic Arabs swarmed out of the desert in the 7th century to carve out an empire that stretched from Spain to the Chinese frontier, why the Mongols failed to conquer western Europe, and where those unique, sea-borne raiders, the Vikings, fitted into the story of kingdoms versus nomads.