An ancient Apollo statue landed in Cleveland and touched off an international outcry

The Aboutaams smiled. It's our newest acquisition, one said. It's quite special.

The brothers whisked off the cloth. Bennett couldn't breathe.

On the table lay remnants of an ancient bronze statue. Even in fragments, he could see the outlines of a graceful adolescent. His back was strong and lean. His left leg curled behind his right. Wide almond eyes stared at the ground.

This wasn't just any sculpture. This was Apollo the lizard slayer, created by Praxiteles in the fourth century B.C. The Greek sculptor was the first to craft a nude female body and the first to portray gods as intimate, human-like creatures. Praxiteles' work changed the direction of Western art — yet no living person had seen an original piece. Historians believed they perished long ago.

Bennett instinctively thought he was looking at an original. And if it was indeed authentic, it was impossible to quantify how important the piece was. "It's as if there were no existing works by Michelangelo — then suddenly one appeared," he explains.

The curator immediately phoned Katharine Lee Reid, the Cleveland museum's director at the time. He had to act quickly. Reid gave her consent.

The Aboutaams and Bennett talked for hours. By the time they were done, the statue was promised to Cleveland.

On the plane home, Bennett couldn't sleep. Worry sank into his gut. It couldn't be this easy, he thought. The piece was too important. Something would go wrong.

He just didn't know what.

The art world had changed since Bennett's Harvard days in the '80s, when professors lectured about the importance of preservation. "We are mortal, but art is permanent," Bennett says.

At the time, budding curators learned that their principal responsibility was to protect art for future generations. In essence, they were its legal guardians. It mattered not where a piece had come from, just so long as it was safe.

So great discoveries like the Apollo were heralded, their finders dined and celebrated.

But the art world was forced to confront a new landscape with the fall of East Germany. That's when the West got its first glimpse of Nazi records, proving that many famous works housed in the world's museums had been stolen from Jewish homes. Holocaust survivors and their kin began a very public campaign to get them back.

Italian and Greek authorities jumped into the debate. They too believed that tombs had been raided and antiquities stolen from their soil. Suddenly, the conversation turned from preservation to rightful ownership. And museums, long seen as noble custodians, found themselves in the unfamiliar role of bad guys.

"It became apparent that the museums were on the wrong side of the acquisitions debate," says Jenifer Neils, a professor at Case Western Reserve.

The antiquities market boasts annual sales of $100 to $200 million. For dealers, there's always been an incentive to hide the history of a work. With fortunes to be made, many had adopted a don't-ask-don't-tell policy.

Museums weren't particularly diligent either. In many cases, it was virtually impossible to prove that an item had been stolen. Tomb robbers, after all, aren't prone to videotaping their raids. So there was rarely concrete evidence of a work's illicit travels.

Then suddenly there was.

Giacomo Medici was one of the world's most connected dealers, supplying the globe with classic Italian art. But Italian police had long been suspicious of Medici. With the aid of Swiss authorities, they raided Medici's Geneva warehouse in 1995. There they found hundreds of photos, clearly showing that much of the work he sold had been stolen from Italian tombs.

One of Medici's closest associates was Robert Hecht, an American dealer who'd arranged hundreds of transactions between Medici and U.S. museums. In 2005, Italian police charged Hecht with conspiracy to traffic in looted art. It was the beginning of a massive treasure hunt.

Armed with tangible evidence and moral outrage, the Italian police started going after American museums, who could no longer feign ignorance. Mounting public pressure and the threat of massive lawsuits caused museums to react as they never had before. The Metropolitan Museum of Art in New York gave back 21 works, including a rare terra-cotta wine vase from 600 B.C. that had cost $1 million in 1972.

After much debate, the J. Paul Getty Museum in Los Angeles agreed to return 40 works. The Princeton University Art Museum, the Museum of Fine Arts in Boston, and the University of Virginia Art Museum all returned pieces as well. Most of these works are now being displayed in Italy's Quirinal presidential palace.