Decorated plates and bowls “of fine workmanship” dating back to the 13th century have been recovered off the coast of Tuscany, a rare discovery by Italian submarine police. During a routine diving exercise near the coastal areas of Pisa and Livorno, officers found several plates and bowls and numerous fragments, the Guardia di Finanza police said on Wednesday.

The recovered items most likely come from the same period and a single naval shipment, police said, adding they were turned over to culture ministry experts, a statement said. The experts identified the artefacts as 13th century examples of etched pottery from Savona, a port city in the northwest of Italy, but archaeological investigations were ongoing, police said.