NY Daily News Archive via Getty; Bettmann/Getty From left: John F. Kennedy and Marilyn Monroe
Part myth and part little-known truth, the relationship between Marilyn Monroe and John F. Kennedy has become the stuff of legend. Now, some tangible pieces of that history — including a signed guest book, rare photographs and a film reel of the iconic "Happy Birthday, Mr. President" performance — are headed to the auction block.
Doyle Auction House is overseeing the sale of a lot of items that once belonged to Arthur Krim, a former film executive, and Dr. Mathilde Krim, the founding chairman of the Foundation for AIDS Research.
Among the items listed for sale are a signed guest book and collection of original photographs from the star-studded 45th birthday celebration for Kennedy, held at Madison Square Garden on May 19, 1962, and the reception held after, at the Krims' New York townhome.
The celebration was notable for its attendees — including top entertainers of the time such as Ella Fitzgerald, Henry Ford and Harry Belafonte — but even more so for the now-legendary performance by Monroe, who sang to the president while wearing a skin-tight, rhinestone-bedecked Jean Louis dress into which she had been sewn for the occasion.
"Arthur [Krim] was high up in politics and arranged the gala at Madison Square Garden," Peter Costanzo, senior vice president of Doyle Auction House, tells PEOPLE.
According to Costanzo, the Krims maintained some 40 years' worth of guest books, the most noteworthy of which are from the May 1962 event.
"We have the signatures of both JFK and Marilyn Monroe and it's the only known example [of a document] signed by both," Costanzo says. The lot also includes 18 originally stamped photos taken that night, including a copy of a once "heavily suppressed" photo, and the only to show JFK, Robert F. Kennedy and Monroe in a room together.
The final piece in the lot is a film reel of Monroe's iconic "Happy Birthday" performance.
The lot — estimated to sell for $40,000 to $60,000 dollars — is especially noteworthy considering the mystery surrounding Monroe's relationship with both JFK and Robert Kennedy.
Rumors about Monroe's alleged affair with JFK were spurred in part by her sultry "Happy Birthday" performance at his birthday celebration.
"What happened to Marilyn Monroe is one of the great mysteries of the 20th century," biographer James Spada told PEOPLE in 2012, ahead of the 50th anniversary of Monroe's death.
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Though Spada doesn't believe there's any proof that the Kennedys were responsible for Monroe's death, he said "it was pretty clear that Marilyn had had sexual relations with both Bobby and Jack."
All three of their lives would be cut short — Monroe's at age 36 on Aug. 5, 1962, of a barbiturate overdose followed by JFK's assassination on November 22, 1963, and Bobby's assassination on June 5, 1968.