In the summer of 1495, King Hans of Denmark and Norway anchored his warship off the southern coast of Sweden. While Hans was on land, his vessel—known as Gribshunden or Griffen—mysteriously caught fire and sank to the bottom of the Baltic Sea.Hans was on his way to Kalmar, where he hoped to be elected king of Sweden and reunite the broader Nordic region under a single ruler. As such, Hans brought many opulent status symbols, including luxurious foods and spices, to help persuade the Swedish leadership to agree to his plan.Remarkably, many of those foods and spices have survived underwater...