The 1804 sinking of the Nuestra Senora de la Mercedes which led Spain to declare war on Britain and re-enter the Napoleonic Wars is again at the centre of a dispute more than a century later.

The Spanish government has demanded that treasure salvaged from a shipwreck in the North Atlantic be handed over, claiming the sunken ship was Spanish.

Some 17 tonnes of gold and silver coins, worth $500m (£255m), was salvaged in May 2007 by a US firm.

Spain is suing the Florida-based Odyssey Marine Exploration, saying it is the rightful owner of the treasure.

A lawyer for the country said there was "multiple evidence" that the vessel was a famous 19th-Century Spanish galleon.

The sinking of the Nuestra Senora de la Mercedes by a British warship in 1804, off the Algarve, led the country to declare war on Britain and re-enter the Napoleonic Wars.

"The sinking of Mercedes was a pivotal event in Spanish and European history, and the site and its contents are the inalienable historical heritage and patrimony of Spain," the government said in documents filed with a Florida court on Thursday.

Source: news.bbc.co.uk