Marie Antoinette was the King of France.
Marie Antoinette . In April 1770 , upon her marriage to Louis-Auguste , heir apparent to the French throne , she became Dauphine of France . On 10 May 1774 , when her husband ascended the throne as Louis XVI , she became Queen of France and Navarre , a title she held until September 1791 , when , as the French Revolution proceeded , she became Queen of the French , a title she held until 21 September 1792 .