The Spanish government filed documents at a Florida court last Thursday to back its claim to be the rightful owner of some 17 tonnes of gold and silver coins, worth $500m, which was salvaged in May 2007 by the Odyssey Marine Exploration company. Spain’s lawyer, James Goold, said there was “multiple evidence” that the treasure came from a famous 19th century Spanish galleon, the Nuestra Señora de la Mercedes, whose sinking by a British warship in 1804, off the Algarve, led the country to declare war on Britain and re-enter the Napoleonic Wars. The head of the treasure-hunting firm, Greg Stemm, said he hoped he could reach a “collaborative solution” to the long-running dispute with Spain. He said however that even if the wreckage was identified as the Nuestra Señora de la Mercedes, Spain would have to prove both ownership and that it did not abandon it. An agreement with Spain could help unblock another Odyssey project just off Gibraltar. The company has a contract with Britain’s Ministry of Defence to excavate a wreck believed to be that of the English warship HMS Sussex, which sank in a storm with valuable cargo. But the project has been plagued with diplomatic pitfalls over the status of waters around Gibraltar and, despite a tentative solution hammered out last year, remains temporarily shelved. Odyssey would like a better relationship with Madrid because Spain is believed to hold title over hundreds of wrecks scattered around the globe.