The two leading ladies of this delightful narrative could hardly have been more unlike, except for the fact that both were beauties and incorrigible flirts, Lady Georgiana Spencer, who married the exalted Duke of Devonshire in 1775, when she was seventeen, was much the more beautiful and by far the more generous, all heart and -- in practical matters -- no head. Lady Elizabeth Foster, who married the same Duke in 1809, when she was fifty-two, having been his mistress for twenty-five years, was all head and very, very little heart. Yet each was the other's closest friend and confidante. To be fair to Lady Elizabeth, which isn't altogether easy, she was calculating not only by inclination but of necessity. An imprudent marriage had left her penniless, and when the compassionate Georgiana offered to shelter her, and the lethargic Duke found her appealing, "poor, dear Bess" saw the role she could play. Unhappily, the Duke was the only man Georgiana was ever to meet who did not find her sexually enticing, and for the next eight years, until in 1790 Georgiana, Duchess of Devonshire, gave birth after almost sixteen years of marriage, Lady Elizabeth's function in the Devonshire household was to stimulate the Duke's sexual ardor sufficiently to get him to bed with his wife. Her efforts for the common good resulted in her own being twice impregnated by the Duke and having to conceal these pregnancies by European travel, but her experience in secretly bearing children abroad stood her friend in good stead when Georgiana herself -- her duty to the Devonshires accomplished -- fell in love and conceived an out-of-wedlock child. To our solemn and righteous eyes the affairs of this triangle-by-consent may seem shocking, but to spend a few irresponsible hours with the adorable Georgiana, the dopey Duke and the seductive Bess, to move in their swinging company from London mansion to splendid country house, from Bath to Naples to Versailles, is wonderful fun indeed. 

The Two Duchesses by Arthur Calder-Marshally