An artist's impression of how HMS Victory may have looked
A US-based salvage firm is believed to have found remains from the wreck of a British warship which sank in the English Channel in 1744.
Odyssey Marine Exploration is expected to announce on Monday that it has found HMS Victory, the forerunner of Nelson's famous flagship of the same name.
The valuables from the vessel, including brass cannons, could be worth millions of pounds, some experts say.
If confirmed, the find could trigger a row with the British government.
The remains from HMS Victory have been reportedly found in international waters.
But as a military wreck, they officially belong to the British state.
Ahead of the expected announcement at a news conference in London on Monday, Odyssey Marine Exploration's CEO Greg Stemm said the firm was negotiating with Britain over collaborating on the project.
"This is a big one, just because of the history," Mr Stemm was quoted as saying by the Associated Press.
"Very rarely do you solve an age-old mystery like this."
Mr Stemm declined to reveal the exact location of the warship's remains.
"We found this more than 50 miles (80km) from where anybody would have thought it went down," he said.
HMS Victory has been described by some maritime experts as "the finest ship in the world" at its time.
It sank with more than 1,100 seamen aboard, including Admiral Sir John Balchen, in a fierce storm off the Channel Islands.
The ship's exact location has since remained a mystery, despite numerous attempts by salvagers to find it.
The vessel had 100 brass cannons and reportedly some 100,000 gold coins on board.
In 2007, Odyssey said it had salvaged 17 tonnes of gold and silver coins, worth $500m (£343m), from a shipwreck in the North Atlantic.
The Spanish government later sued the company, claiming the sunken ship was a famous 19th Century Spanish galleon.
The case is pending.