19. Which European country's royal family is sometimes known as "the House of Orange"?
From Quiz All Things Orange
The rulers of the Netherlands are descendants of William I, Prince of Orange (1533 -1584), who was the eldest son of William, Count of Nassau. Nassau was a German duchy in what is now Hesse, Germany. When his cousin, René of Châlon, died childless in 1544, William inherited his titles, which included Prince of Orange. Orange was a principality in southwestern France. So the Dutch royal family are actually Germans who take their name from a place in France.
England was briefly ruled by the House of Orange when Mary, the daughter of James II, married yet another William of Orange. After deposing James in what was called "the Glorious Revolution," the couple ruled jointly as Mary II and William III. They had no children, so upon William's death in 1702, the throne passed to his sister-in-law, Queen Anne.