Louis XVI was the real world King of France during the late seventeenth century. He is infamous for causing his subjects to revolt during the French Revolution which had many noblemen across the country executed.
Louis XVI was an incredibly well pampered and overweight man who wore the typical aristocratic clothing of the era.
Louis XVI married Marie Antoinette when she was just 14 and the two led an unhappy marriage. The demon Poirsenus mentioned this to her when mocking her so he could keep her under his control.