The wreck site on a beach in Sligo had never been conclusively traced to a named ship, but the National Monuments Service of Ireland research has now revealed it is the wreckage of the Greyhound, a coastal trading vessel which regularly sailed between its home port of Whitby and Ireland.
Twenty people died when the 23-year-old Greyhound, which had a female owner called Mrs Allely, foundered in a storm in December 1770 near Streedagh Strand, reputedly while carrying a cargo of butter.
It had set sail from Whitby under the command of a Captain Douthard before getting into difficulties off County Mayo.
It anchored off the cliffs at Erris Head before the crew abandoned the ship - but not all would eventually reach safety.
After realising a cabin boy had been left on board, sailors and local volunteers returned to try and save him on a ship called the Galway, but many of the rescuers were dragged out to sea and 20 of them died.
A wreath has now been laid at Streedagh Strand to commemorate the dead.
The wreckage of the Greyhound is well-known in the local area as it is visible at low tide, and local legend suggested that the vessel had been part of the Spanish Armada invasion force in the 16th century.
The National Monuments Service examined timbers and historical accounts to correctly date the remains. Carbon dating techniques established that the wood had come from trees felled in the north of England, thereby ruling out Spanish construction.
Irish heritage minister Malcolm Noonan said: “I know there is a huge amount of local interest in this wreck and that its identity has been a topic of debate for many years, with many calling it the Butter Boat and others thinking it part of the Armada.
"I am very pleased that through archaeological investigation, scientific analysis and historical archival research our National Monuments Service has been able to finally confirm the wreck's identity and the events of December, 12 250 years ago."