Madagascar’s President Hery Rajaonarimampianina, second from right, stands in front of a 110-pound silver bar which was allegedly recovered by Marine archaeologist Barry Clifford in the wreck of William Kidd’s ship May 7 on the Island of Sainte Marie. (Manjakahery Tsiresena/AFP/Getty Images)

Famed explorer Barry Clifford believes — once again — that he has finally found the elusive Adventure Galley, the crown jewel of famed pirate Captain William Kidd’s exploits in the Indian Ocean in the 1600s.

On Thursday, in an elaborate public ceremony, Clifford emerged from the cloudy waters off the coast of Madagascar with a 110-pound silver bar he believes is from Captain Kidd’s ship Adventure Galley.

“After 15 years of research and expeditions to Madagascar, I have made an incredible discovery,” Clifford told the History channel, which was on hand to record the find. “While investigating the shipwreck I believe to be Captain Kidd’s Adventure Galley I uncovered a giant silver bar. All the evidence points to it being part of Captain Kidd’s treasure. It’s a huge find for my team but an even bigger find for Madagascar and world history.”

The only problem: It might not be from Kidd’s ship.

“If there was only one ship that had been sunk in that harbor I’d be much more confident that it related to Captain Kidd. But a number of ships had sunk there,” said Robert Ritchie, a historian and author of “Captain Kidd and the War against the Pirate.” “I’m doubtful, but who knows? It could well be from the Adventure Galley. But it would be from one of Kidd’s men more than from Kidd himself.”

This wouldn’t be the first time that Clifford thought he had found the ship. In 2000, when Clifford first discovered the site, he announced that after years of searching, his team had practically stumbled upon the wreckage.

“We almost dropped anchor on top of the wreck,” Clifford told the Los Angeles Times shortly after the discovery.

But the very reason for the Adventure’s allure also helps explain why attempts to find it have proven to be so difficult.

Historians, treasure hunters and archaeologist have known the general location of the ship for years. The Adventure is believed to have been abandoned in the relatively shallow waters off the coast of Madagascar, near the isle Sainte Marie, which in historical documents was referred to as the “Island of the Pirates.”

Kidd, having returned from his fairly modest conquests in the Indian Ocean, went there to start afresh. It was time to abandon the battered and weather-worn Adventure for a new vessel.

There is some dispute about what exactly happened, but some historians say that Kidd stripped the ship of everything that they could carry — treasure and supplies — and loaded them onto another ship he had commandeered. He set the Adventure on fire and allowed it to sink to the bottom of the harbor.

With the new ship — and his treasure — he sailed home, stopping first in the Caribbean, then finally arriving in New York. Accused of piracy, Kidd was arrested and sent to England, where he would be hanged in 1701 for piracy and the murder of one of his crewmen.

There is, however, quite a bit of lore about what exactly happened to all of his treasure. Some believe that Kidd buried or sank treasure practically all over the world — in New York, the Caribbean near Hispaniola and near Madagascar.

A picture taken May 7 shows a 110-pound silver bar which was recovered by Marine archaeologist Barry Clifford, allegedly in the wreck of William Kidd’s ship, off the Island of Sainte Marie. (Manjakahery Tsiresena/AFP/Getty Images)

Ritchie says that the evidence suggests that the authorities collected all of Kidd’s treasure that they could find and put it on the same ship that carried him to England for his trial. At the very least, Kidd took all of it with him when he sailed away from Madagascar, Ritchie said.

Still, that hasn’t stopped Clifford and others from searching the remote waters off Madagascar for what artifacts of Kidd’s they can find. The only problem is, the waters near Sainte Marie is where a lot of other ships had met their end. According to Ritchie, that is also what makes the discovery of this silver ingot no more definitive than any previous discoveries that have been made there.

“We know he stripped the Adventure Galley of everything that he could,” Ritchie said. “I can’t imagine him leaving big silver bars behind.”

“I don’t doubt that there’s much silver there. I’m just not sure at all that it’s Captain Kidd’s,” he added.

Indeed, when Clifford first came across wreckage he believed to the Adventure more than 15 years ago, he later discovered that there were actually several other ships that had sunk there. They were able to positively identify some of them, but none — perhaps until this week — were definitively identified as the Adventure.

Despite those setbacks, Clifford concluded that Kidd’s Adventure couldn’t be far from those other sunken ships. And he may well be right.

Clifford’s find will need to be verified, of course. And whether or not that silver bar belongs to Kidd, Clifford’s’ handling of the discovery — by inviting the president of Madagascar and promptly handing the “treasure” over to local authorities — will help to forestall any future battles over who owns whatever is eventually found — whether it once belonged to Kidd or not.

And the victory for Clifford is not in the treasure, but in adding another discovery to his name.

Clifford, once dubbed the “Pirate Prince,” catapulted to fame with the 1985 discovery of the Whydah and its treasure-laden ruins off the coast of Cape Cod. And last year, Clifford claimed to have found Christopher Columbus’s Santa Maria.

The History Channel was present Thursday documenting the newest development in the long search for Captain Kidd’s flagship. And they have already arranged for everything found at the site to remain in the hands of the Madagascar government.

The eight-part series will air later this year.