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A prominent coin collector thought he had some valuable, ancient pieces with a problem: They shouldn't have been taken out of Italy.

The coins turned out to be fakes, but they led to very real trouble for the collector, noted Rhode Island hand surgeon Dr. Arnold-Peter Weiss. He pleaded guilty Tuesday to criminal charges in a case that set the numismatic world abuzz.

It also added to a string of court cases and disputes over collecting and trading in objects that Italy and other countries consider looted pieces of their cultural patrimony.

An orthopedics professor at Brown University's Alpert Medical School and author of a hand-surgery textbook, Weiss is no less accomplished in the coin world.

A collector and investor for 35 years, he's been on leadership boards of the American Numismatic Society and the Rhode Island School of Design's art museum, according to his biography on Brown's website. The coin society said no one was available to comment Tuesday on Weiss' history with the organization; a RISD spokeswoman didn't immediately return a call.

Weiss was arrested in January amid a coin auction at the posh Waldorf-Astoria hotel, planning to sell what was listed as a silver tetradrachm, a Greek coin from the fourth century B.C., according to a criminal complaint. Weiss expected it to net about $350,000, according to the complaint.

Under Italian law, antiquities found there after 1909 can't be removed from the country. But Weiss said in a secretly recorded conversation: "I know this is a fresh coin. This was dug up a few years ago," according to the complaint.

Modern metal detectors have turned up long-buried coins, often obvious because of the way they have been cleaned, among other signs, Weiss told a Manhattan court Monday.

He acknowledged that he knew what to look for, was aware of Italy's antiquities rules and believed that two other coins that he had in his possession at the auction had been found after the 1909 deadline. All three coins were described as having been found in Sicily.

The other two coins were similarly ancient decadrachms, worth about $1.2 million apiece — or so Weiss thought at the time.

"I believed that the coin was authentic" in each instance, he said.

But after his arrest, an expert examined them and found they "were, in fact, forgeries — exquisite, extraordinary forgeries, but forgeries nonetheless," Manhattan Assistant District Attorney Matthew Bogdanos said.

Still, Weiss was criminally implicated because he believed what he had were illegally obtained coins.

Under his plea deal, Weiss must forfeit his interest in 23 coins seized from him when he was arrested, perform 70 hours of community service and write an article about the problem of trading in unprovenanced coins — those of uncertain origin — and "the continuing threat of this practice to the archaeological record." He also must try to get it published in the numismatic society's magazine or a similar venue.

The article "will raise needed awareness about unprovenanced coins and will promote responsible collecting among numismatists," district attorney's office spokeswoman Joan Vollero said.

Weiss and his lawyers declined to comment after court.

Italy has aggressively campaigned in the last decade to get back ancient Roman, Greek and Etruscan artifacts the government says were looted or stolen. Institutions including the Metropolitan Museum of Art in New York and the J. Paul Getty Museum in Los Angeles have agreed to return various items.

There have been some criminal prosecutions, including a Rome trial of a former Getty assistant curator. It ended in 2010 with a judge saying the statute of limitations had expired.

In April, federal prosecutors in Manhattan announced that a Renaissance painting and a Roman sculpture from about the first century were being returned to Italy after turning up at auction houses in New York.

Other countries, including Turkey and Greece, also have taken action in recent years to reclaim antiquities.

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