Georgiana, The Duchess of Devonshire, was born Miss Georgiana Spencer and yes, she was actually related to Princess Diana - she was her great-great aunt. Georgiana, or Gee as she was called, was born in 1757 and she therefore most certainly must be said to have lived in a very different age – a different century even -than Princess Diana did. Still, the resemblance to Princess Diana and her life was striking.
Gee married one of England's most beloved bachelors, William Cavendish, the 5th Duke of Devonshire. She quickly became a role model for fashion and beauty for the English upper class - especially her hairstyles were extraordinary and trendsetting! Gee also got involved in political topics, wrote poetry and short stories and yes, then her husband was unfaithful to her.
Right now, you can get the story of Miss Georgiana Spencer in the movie THE DUCHESS hereat Kino Club (and you can also watch the movie about Diana if you should be inspired to go look for similarities).