WARSAW, POLAND—Eighteen silver coins dating to the seventeenth century were discovered in a defensive tower at Czluchów Castle in northwestern Poland, according to a report in Science & Scholarship in Poland. Michal Starski of the University of Warsaw said the valuable coins, which had been minted for foreign trade, may have been hidden during a period of war known as the Deluge, between 1655 and 1657, when the castle was captured by Swedish forces. “The Czluchów fortress resisted the Swedes for a long time,” Starski said. “The siege lasted for several months—ultimately, in the winter of 1655-56, when the surrounding lake fortress froze, the invaders captured it.” A similar cache of coins was found at a nearby cemetery in the beginning of the twentieth century. Starski thinks the coins may have come from the same collection. For more, go to “Off the Grid: Krakow.”