Coins on the ocean floor at the Black Swan site (courtesy of

Hidden behind a fabulous sunken treasure recovered from a wreck in the Atlantic Ocean lays a story of secret diplomatic cables and Nazi art thieves, according to a revelation from WikiLeaks documents.

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Consisting of 500,000 silver coins weighing more than 17 tons, hundreds of gold coins, worked gold, and other artifacts, the so-called Black Swan treasure has been at the center of an acrimonious international legal battle ever since it was discovered in 2007 by underwater robots from Odyssey Marine Exploration, a Florida-based treasure-hunting company.

It wasn’t a fair confrontation, according to leaked documents released by WikiLeaks.

London’s Guardian newspaper, one of the news organizations which receive the cables directly from WikiLeaks, reported that U.S. officials offered to help Spain in the court fight over the sunken treasure.

In exchange, they asked assistance for returning a valuable Impressionist painting looted by the Nazis during WWII.

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“The cables indicate that the U.S. government provided confidential documentation on Odyssey to Spain,” said Odyssey Marine Exploration in an emailed statement.

The fight over the Black Swan treasure started when Odyssey recovered the coins, valued at as much as $500 million, and shipped it straight to the United States.

Spain immediately filed a claim arguing that that the coins originated from the Nuestra Senora de las Mercedes, a 36-gun Spanish frigate which sunk off the coast of Portugal in 1804 in a battle with four British Navy ships.

According to an international maritime law known as doctrine of sovereign immunity, active duty naval vessels on a non-commercial mission remain the property of the countries that commissioned them. The wreck and its cargo would then be the exclusive property of Spain.

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Odyssey argued there was not enough evidence to prove the wreck, which they codenamed “Black Swan,” was the Mercedes and even if that were the case the ship’s last voyage, from Montevideo to Cadiz, was commercial in nature. The majority of coins on board were owned by private merchants, not by Spain, Odyssey insisted.

The Wikileaks revelations arrived while the case is currently pending in the Eleventh Circuit Court of Appeals in Atlanta, and the treasure is kept in a secure, undisclosed location.

Dating to July 2, 2008, the cable reported a conversation between the Spanish culture minister, César Antonio Molina, and the U.S. ambassador in Madrid, Eduardo Aguirre.

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The discussion focused around the Black Swan treasure and the attempts by an American citizen, Claude Cassirer, to recover Camille Pissarro’s “Rue St Honoré. Après-midi. Effet de Pluie” (1897), which currently hangs in Madrid’s Thyssen-Bornemisza Museum.

“The ambassador noted that while the Odyssey and Cassirer claim were on separate legal tracks, it was in both governments’ interest to avail themselves of whatever margin for maneuver they had, consistent with their legal obligations, to resolve both matters in a way that favored the bilateral relationship,” the cable stated.

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Cassirer’s claim was well known, as it was mentioned in a cable filed months before. The story goes that Cassirer’s Jewish grandmother was forced in 1939 to sell Pissarro’s depiction of a rain-soaked Paris boulevard for $360 in order to obtain an exit visa from Germany.

Baron Hans Heinrich Thyssen-Bornemisza acquired the Impressionist painting in 1976.

“In the early 1990s, the Spanish government purchased the collection and built the current museum. In 1958, Mrs. Cassirer received a DM 120,000 restitution payment for the disappearance and provisional dispossession of the painting, but retained full right to the painting,” said the cable.

The embassy cable reports that the Spanish culture minister Molina refused to trade the Odyssey dispute with the looted painting: “The minister listened carefully to the ambassador’s message, but he put the accent on the separateness of the issues.”

He added that the collection technically belonged to a foundation, thus there was little the Spanish government could do about it.

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Despite Molina’s refusal, the leaked cables reveal that as early as 2007, the U.S. embassy handed over to Spanish authorities the customs import documents that Odyssey had filed when bringing the hoard of coins into the United States.

“The information was confidential and to be used only for law enforcement purposes,” embassy officials warned Spain’s director of customs.

Odyssey officials are waiting for additional information “before taking any specific actions,” stated Greg Stemm, Odyssey’s chief executive officer.

“The possibility that someone in the U.S. government came up with this perfidious offer to sacrifice Odyssey, its thousands of shareholders, and the many jobs created by the company in exchange for the return of one painting to one individual is hard to believe,” the company said in a statement.

“It is hard to believe that this really happened. It sounds like something out of a Hollywood script.”