Divers in Tonga have discovered a shipwreck believed to be a pirate vessel that folklore says sank in the 19th century with a hold full of treasure, officials in the Pacific nation said Thursday.

The Port-au-Prince, a British privateer, was attacked by local warriors in 1806 after arriving in Tonga and most of its crew were massacred on the orders of King Finau 'Ulukalala II, Tonga's tourism ministry said.