And she described how Robert’s death brought anguished memories flooding back about JFK’s murder five years earlier.
President Kennedy was assassinated in Dallas, Texas, on November 22, 1963. Robert Kennedy was shot dead in a hotel in Los Angeles on June 6, 1968.
The three-page letter dated July 16, 1968, was written to Vicomtesse Jeanne-Marie De La Rochefoucauld, whom she had known since her youth.
It reads: “I was so touched by your letter. You feel so strongly all the unutterable things, I suppose the world does, but it affects me very much coming from you.
“Pease do not feel offended that your letters to me at the time of President Kennedy’s death were not answered – I received more than one million letters and battalions of secretaries and volunteers went through them.
“After months they were arranged in some sort of categories but it was impossible to answer them all.
“I read eight letters in the first days afterwards then I never read any more nor do I ever wish to – I could not survive it.
“Every single letter has been saved and will be forever kept in his library as will the letters for Robert Kennedy.
“But I am so very glad that your letter for Robert Kennedy, my beloved and tragic brother-in-law, reached me. I thank you with all my heart.”
The Vicomtesse, who was born in Paris, died aged 82 in 2004.
The letter has been put up for sale with New York-based dealer Lion Heart Autographs by a private collector who purchased it from the family.
Hailing the letter’s signi cance, David Lowenherz, owner of Lion Heart Autographs, said: “It is a unique, heart-wrenching account.”