LISBON, Portugal — Archaeologists in Portugal say they have discovered off Lisbon a 400-year-old shipwreck they describe as the most important underwater find in the country for two decades.

The municipal council of Cascais, a town near Lisbon, said Monday the Portuguese ship was involved in the hugely lucrative spice trade between Portugal and India. Peppercorns, cowry shells used in the slave trade and bronze artillery pieces litter the wreck site.

The council said in a statement the wreck was found last month during dredging at the mouth of the River Tagus, on Portugal’s Atlantic coast.

Preliminary excavations have also found porcelain dating from the period of China’s Wanli Emperor in the late 16th and early 17th centuries.

The find came during an offshore mapping project compiling an inventory of wrecks.