The author of "Empress Bianca" also wrote a 1992 New York Times best selling biography of what princess?
Empress Bianca: Empress Bianca, the first novel by Lady Colin Campbell, was initially published in June 2005. Lady Colin Campbell:  They include biographies of Diana, Princess of Wales, which was on "The New York Times" bestseller list in 1992, and Queen Elizabeth The Queen Mother.
Diana, Princess of Wales