Aristocracies or nobilities dominated the social, economic, and institutional history of all European counties until only a few generations ago. The relics of their power, in traditions and behaviour, in architecture and the arts, are still all around us. This short introduction shows how ideas of aristocracy originated in ancient times, were transformed in the middle ages, and have only fallen apart over the last two centuries. The myths in which aristocracies have always sought to shroud themselves are stripped away, but the true sources of their enduring power are also revealed. Their outlook and behaviour affected the rest of society in innumerable and sometimes surprising ways, but perhaps most surprising was the way in which a centuries-old aristocratic hegemony crumbled away over the last two hundred years. In this Very Short Introduction William Doyle considers why this happend and what remains today.