Like the fictional Cora Levinson Crawley, Lady Grantham on “Downton Abbey,” there were many American heiresses in the Edwardian era who married land-rich but cash-poor British aristocrats. Women like Consuelo Vanderbilt and sisters Mary and Daisy Leiter swapped money for titles. The newspapers called them Dollar Princesses. We will look at some of these heiresses, their lives, their spouses and the British country houses that their money rescued.