The Department of Homeland Security just returned a trove of artifacts deemed to be the property of the French government, and five gold ingots that were likely smuggled to the U.S. decades ago and which landed in a Bay Area auction house, were among them.

The five gold ingots, used as currency by Chinese traders, were among the treasures picked up by some discreet divers around 1975 from the ocean floor off the coast of France. The ship they had been on, the Prince de Conty, was a frigate that belonged to the French East India Company, and it was just ten miles from shore, about to return to port at Lorient, France, when it sank amid fog and rough seas and an apparent navigational error by its captain on December 3, 1746. On board was tea, lots of Qing Dynasty porcelain, and around 100 gold ingots embossed with Chinese characters — each worth about $25,000 in today's dollars. Nearly 200 men drowned, and only 45 onboard survived the wreck.

Salvage efforts were thwarted by rough seas in 1747, so the shipwreck became the stuff of local lore in Brittany for over two centuries, until a group of divers decided to secretly check it out for themselves in 1974.

As the New York Times explains, the story gets a bit murky after that, but one photograph of several ingots lying on the ocean floor and taken by one of the divers who returned to loot the site in 1975 ended up being a key to the eventual investigation by Homeland Security Investigations and France's Underwater Archaeology Research Department — and it involved Antiques Roadshow!

It's not clear how many ingots are still out there, or how many might have been melted down and sold to pad someone's nest egg. But five remained together and intact, with the Chinese characters, only to be presented by a French woman to the cameras of Antiques Roadshow in 1999, in Tampa, Florida. The woman said the ingots had come from a different shipwreck, off Western Africa — but Michel L’Hour, the French investigator with the Underwater Archaeology Research Department, would later call out the fact that the woman was likely lying. She presented the photograph of the ingots, the same one he knew was taken from the Prince de Conty shipwreck, which showed a sea urchin and a starfish beside the ingots — neither species is native to West African waters, but they are found off the coast of France. And L'Hour also determined the woman was the sister of the wife of the diver who photographed the loot.

The ingots resurfaced at a Santa Rosa auction house in 2018, Stephen Album Rare Coins, on consignment. And it was there that they were seized in a federal raid, following their being spotted by L'Hour and a network of informants who hunt down such items on the internet.

As KPIX reports, they were returned to France this week, along with several other looted items that belong to the French government, including a 3rd century gold coin, and a human skull stolen from the Catacombs of Paris.

"We are very grateful to the United States for the action taken by its services to return these artifacts and emphasize the quality of cooperation between the French and American customs, police, and judicial services in the fight against trafficking in cultural property,” said Philippe Etienne, Ambassador of France to the United States, in a statement.

Per the Times, the return of the ingots was slightly delayed by a dispute of ownership — this time from the Chinese government. The Chinese said the 13-ounce gold bars should belong to them, but United States Customs and Border Protection determined that the ingots were a "common form of currency" used by traders in the 1740s, and therefore not cultural heritage property, as the Chinese contended.