The wreck was found well-preserved at 40ft below sea level off the coast of Portugal this week.
Spices, ceramics and cannons engraved with Portugal’s coat of arms were discovered around the wreck.
It is believed the ship was returning from India when it sank sometime between 1575 and 1625, which was the height of Portugal’s rich spice trade with Asia.
The discovery is part of a 10-year archaeological project supported by the town of Cascais, the Portuguese government and navy, and Nova University in Lisbon.
Jorge Freire, project director, said: “From a heritage perspective, this is the discovery of the decade.” He described it “the most important find of all time” for the country.
Portugal’s Minister of Culture, Luis Mendes, said the mouth of the Tagus River was considered a “hotspot” for wrecks.
“This discovery came to prove it,” he added.
Cowry shells – considered currency in the slave trade – were found among the wreck.
Divers also discovered bronze artillery pieces and Chinese porcelain.