Bonnie Prince Charlie went into hiding after losing at Culloden
Divers say they have found the wreck of a vessel which may have been sent to relieve Bonnie Prince Charlie after his 1746 defeat at the battle of Culloden.
The team says artefacts recovered from the ship, found off the Anglesey coast, suggest it may have been bringing supplies from the King of France.
The Prince - Charles Edward Stuart - was at the time in hiding after the failure of the Jacobite Rebellion.
Divers will fully excavate the wreck to determine its historical significance.
Over the centuries, hundreds of ships have been wrecked off the rugged north Wales coast.
But divers who explored this 18th century vessel found items including a rare ring seal of Mary Queen of Scots.
They think this may have been carried as proof of the intentions of the crew and led them to believe it might have been a supply ship.
Diver Steve Dunmore describes some of the things that could be in the shipwreck off Angelsey
However, the BBC's Wyre Davies said: "The name of the ship is not known and, thus far, comparatively few items have been recovered.
"If this really is as historically significant a find as its backers suggest - there are still many questions to be answered."
George Dalglish from the National Museum of Scotland confirmed that he authenticated a copper matrix seal, bearing the insignia of Mary Queen of Scots, which the divers say was recovered from the wreck.
He said he would not want to speculate on the origins of the seal or the nature of the wreck.
The museum is aware that during the Victorian period some glass copies were made and in the National Museum of Scotland collection, there is a gold enamel template which dates to the Victorian era, also bearing the arms of Mary Queen of Scots.
The museum added that it was an "interesting find" but would not be drawn any further about the nature of the wreck.
The Battle of Culloden - the last to be fought on British soil - took place on 16 April, 1746.
Defeat marked the end of the "Young Pretender" Prince Charlie's bid to return the Stuart dynasty to the British throne.
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