JFK's Secret Love Letters Sold for $115,537

John F. Kennedy's secret love letters to Gunilla von Post, a Swedish woman with whom Kennedy had had an affair, were sold for $115,537 Wednesday night, according to Legendary Auctions, which carried out the sale.

After widespread national and international interest, the letters went to an anonymous West Coast collector, according to Julie Stoklosa, a spokesperson for auction house.

The $115,537 price included an 18.5 percent buyer's premium, Stoklosa said.

Three weeks before Kennedy married Jacqueline Bouvier, he met von Post and the two began a fleeting but passionate romance. The relationship continued after Kennedy was married, von Post says.

Kennedy's relationship with the Swedish woman was documented in a series of poignant letters and telegrams. Von Post kept the correspondence locked away, so the letters were never made public until she put them up for auction last month.

In the letters, Kennedy expresses, in his scrawling longhand, his feelings for von Post.

"Under that beautiful, controlled face that still haunts me -- beats a warm heart," Kennedy wrote in a letter dated Dec., 18, 1954, according to a transcript on LegendaryAuctions.com.

The two met on the French Riviera in the summer of 1953. He was 36, and she was 21. They danced all night, and parted with a passionate kiss.

On June 28, 1954, during the summer after he was married, Kennedy wrote to von Post, saying: "I might get a boat and sail around the Mediterranean for two weeks -- with you as crew."

Kennedy Wrote to Swedish Love From Hospital

But their plans for a secret rendezvous fell apart when Kennedy badly injured his back.

In November 1954, he wrote to her from the Hospital for Special Surgery in Manhattan. His letter seemed full of longing.

"I am still in the hospital after two months. I was terribly disappointed that at the last moment I was not able to come to Europe, especially when you were going to be in Paris and we could have had such a good time. …" He wrote that he was going to see her without fail if she wasn't "all settled down" by then.

In the same letter, he wrote at the end: "Is there any chance you will be coming to the U.S.?"

Von Post, now 78 years old, first revealed the affair in a 1997 book, "Love, Jack." In an interview that year with ABC News' "20/20," she described how her heart went "boom-boom-boom-boom."

"I was very happy to hear from him, but I said, 'He's a married man,'" she told "20/20."

It wasn't until the following year that the two got together, slipping away to an old castle in Sweden.

"I borrowed him for a week, a beautiful week that no one can take away from me," she told "20/20."

Bidding for Letters Started at $25,000

John Reznikoff, president of University Archives, said the correspondence was "seeping with regret. ... These two people wanted to be together, and it wasn't meant to be."

"We've heard all the rumors. We know that JFK had many mistresses, but here we have proof. But not tawdry ... a sensitive love affair that you can understand through the correspondence."

Von Post has described the feelings between her and Kennedy as "electrical." But it wasn't to last.

In his final letter to von Post in August 1955, Kennedy wrote as though he sensed their destinies were drifting apart.

"I just got word today -- that my wife and sister are coming here. It will all be complicated the way I feel now -- my Swedish Flicka. All I have done is sit in the sun and look and the Ocean and think of Gunilla ... All Love, Jack."

The bidding for the letters started at $25,000. But Doug Allen, president of Legendaryauctions.com, knew they would fetch far more.

"We'll let the market determine the real economic value of this," he told ABC News last month. "My guess is they'll go for $100,000."

He was right.

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