Portraits can reveal surprising facts about their sitters. Christian IV, King of Denmark (r.1588–1648) suffered from a rare condition, Plica polonica, which caused a lock of hair to bind together. Rather than attempt to remove the lock, Christian IV kept his hair plaited and even hung a large pearl from it. His courtiers began to copy his plait and it is common to see portraits of seventeenth-century sitters wearing one long lock of hair by their ear.