(CNN) Archeologists have found a centuries-old shipwreck off Portugal's coast near Lisbon, a local mayor's office said Saturday.

Aboard the ship, thought to have sunk between 1575 and 1625, divers found spices, including pepper; Chinese ceramics from the period; and cowries, a type of shell used as currency for the slave trade in some parts of Africa at the time.

The project's science director, Jorge Freire, called it the "discovery of the decade."

"From a conservation perspective, both of the assets as of the ship itself, this discovery is of great patrimonial value," he said.

Maritime archaeologists explore the shipwreck.

Also found were some of the ship's bronze cannons, engraved with the Portuguese coat of arms and the armillary sphere that are still featured in the Portuguese flag.

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