The origin of the House of Orleans is involved in some obscurity. The city of Orleans, from which the duke takes his title, was the Aurelium of imperial Rome. The first Duke of Orleans with whom history makes us familiar was Philip, the only brother of Louis XIV. Louis XIII., the son and heir of Henry IV., married Anne of Austria. Two children were born to them, Louis and Philippe. The first became the world-renowned monarch, Louis XIV. His brother, known in history as Monsieur, enjoyed the title and the princely revenues of the dukedom of Orleans.