After the tragic assassination of her husband, Jackie Kennedy became close to the British Ambassador to the US, David Ormsby-Gore.
A series of letters have been discovered, showing how the relationship blossomed, but then ended suddenly as she instead chose to marry Aristotle Onassis.
The letters are up for sale at Bonhams, and are expected to be sold between £100,000 and £150,000 ($130,000 to $190,000).
Video journalist: Dan Curtis. Producer: Nadine Dukeson.