<p><b>A deliciously told group biography of the young, rich, American heiresses who married into the impoverished British aristocracy at the turn of the twentieth century ¿ the real women who inspired</b><i><b> Downton Abbey</b><br></i><br>Towards the end of the nineteenth century and for the first few years of the twentieth, a strange invasion took place in Britain. The citadel of power, privilege and breeding in which the titled, land-owning governing class had barricaded itself for so long was breached. The incomers were a group of young women who, fifty years earlier, would have been looked on as the alien denizens of another world - the New World, to be precise. From 1874 - the year that Jennie Jerome, the first known ''Dollar Princess'', married Randolph Churchill - to 1905, dozens of young American heiresses married into the British peerage, bringing with them all the fabulous wealth, glamour and sophistication of the Gilded Age.<br><br>Anne de Courcy sets the stories of these y