SYDNEY.- When British explorer James Cook set out in 1768 in search of an “unknown southern land” called Terra Australis Incognita, he sailed on a navy research vessel called the HMB Endeavour. More than 90 people were on board the ship, described by some historians as homely but sturdy.

Two years later, it dropped anchor off the east coast of what is now Australia, precipitating two centuries of British control. It would go on to transport British troops during the American Revolutionary War and meet its demise in 1778, part of a fleet of ships that historians believe sank off Rhode Island.

For more than two decades, a team of Australian and American researchers have been scouring the waters in search of the wreckage.

Then, Thursday morning, 254 years after Cook set sail, archaeologists at the Australian National Maritime Museum announced that they were “convinced” they had identified the final resting place of what the museum’s CEO and director, Kevin Sumption, called “one of the most important and contentious vessels in Australia’s maritime history.”

But soon after the news conference in Sydney, there was an unexpected response from the museum’s American research collaborator, the Rhode Island Marine Archaeological Project.

From Rhode Island, where it was still the middle of the night, a terse statement appeared on the project’s website. It called the identification of the wreckage “premature” and the Australian museum’s actions “a breach of contract between RIMAP and the ANMM for the conduct of this research and how its results are to be shared with the public.”

The dueling statements raised several questions. Did the Australians jump the gun, announcing the finding without the Rhode Island group’s approval? Why had they chosen to hold their news conference at a time seemingly inconvenient to their American research partners? What, exactly, did the breach of contract consist of? And most important: Had the wreckage of Cook’s famous ship finally been discovered?

The Australian museum did not respond to a request for comment. The Rhode Island project merely shared its previous statement.

The Endeavour was relatively small — less than 100 feet long — and not considered an impressive or significant vessel in its lifetime. But its role in Australia’s history nonetheless means it looms large in national lore.

Cook raised the British flag on what is now called Possession Island in 1770. Eighteen years later, a British fleet sailed into Sydney Harbor to start a penal colony. The mariners raised a flag on land that the British described as Terra Nullius, or Nobody’s Land, although Aboriginal people had inhabited the continent for about 65,000 years.

The modern-day search for the wreckage of the Endeavour began in 1999, when the Australian National Maritime Museum Center agreed to collaborate with the Rhode Island Maritime Archaeological Project, founded by Kathy Abbass with the intention to “study Rhode Island’s maritime history and conduct marine archaeology fieldwork.”

For more than two decades, the teams scanned the Newport Harbor area off Rhode Island. They used the usual methods to identify old ships; surveying construction details, cross-checking historical records and using what’s left of a vessel to model its original form.

When Sumption announced that a wreck in the harbor had been positively identified as the Endeavour, he cited a number of factors, including the historical evidence relating to the ship’s sinking; the schematics of the vessel as recorded in the 1700s; and the use of European timber, as opposed to American timber. Although only 15% of the vessel had survived, the researchers said, Sumption was “satisfied” with his team’s conclusion.

“The last pieces of the puzzle had to be confirmed before I felt able to make this call,” he said. “Based on archival and archaeological evidence, I’m convinced it’s the Endeavour.”

The announcement made headlines around the world.

Anna Clark, a research fellow at the Australian Center for Public History, said, “The fact that the Endeavour generates so much interest and engagement 252 years later really shows what a defining icon it is in Australian history, both in its deep history and also its modern history.”

But the Rhode Island project’s statement quickly overshadowed the original news.

The Endeavour affair comes at a tense time in Australia’s battle over its colonial history. The arrival of the first fleet of European settlers to Sydney in 1788 is commemorated with Australia Day, on Jan. 26. Since the holiday’s beginning, Indigenous Australians have been excluded from celebrations; in recent years, the holiday has been the subject of public protests.

In 1888, when Sir Henry Parkes, father of the Australian federation, was asked how First Nations people might be involved, he remarked that it would serve only to “remind them that we have robbed them.” For many, the holiday is a mark of the country’s shameful treatment of Indigenous people: Invasion Day.

The dispute over whether Cook’s ship has really been discovered also revives criticism that some Australians are too obsessed with the man and the ship.

Ultimately, said Kate Fullagar, a history professor at Macquarie University in Sydney, “the ship itself is not particularly extraordinary in the British naval fleet at the time — except it did last a long time.”

How the matter will be resolved remains murky. The Australian museum later released a statement rejecting the breach-of-contract claim. Sumption has since revised his opinion that the Endeavour has been discovered to “confident” from “convinced.” The Rhode Island project said it would post “the legitimate report” on its own website when it was ready.

From an academic perspective, the Endeavour’s value is limited, some experts say. Wendy van Duivenvoorde, an associate professor of marine archaeology at Flinders University in South Australia, said that “just the finding of an iconic ship has no archaeological value.”

“We don’t answer any questions by finding a shipwreck,” she said.

This article originally appeared in The New York Times.