A cast-aside painting in the style of famed 17th century Dutch master Pieter Brueghel the Younger — which long hung hidden behind the door of a home in northern France — is the real deal.

A secret map of Ireland's coastline played a crucial role in taking down a powerful alliance of pirates that had based itself in the southwest of Ireland in the 17th century.

It’s now in the custody of Dutch authorities, and Polish officials have formally requested its return. The 17th-century oil painting depicts a peasant woman holding tongs with hot coals in one ...