Archduke Franz Karl Joseph of Austria was a member of the House of Habsburg-Lorraine. He was the father of two emperors: Franz Joseph I of Austria and Maximilian I of Mexico. Through his third son Karl Ludwig, he was the grandfather of Archduke Franz Ferdinand of Austria – whose assassination sparked the hostilities that led to the outbreak of World War I – and the great-grandfather of the last Habsburg emperor Karl I.

Maria Carolina was Queen of Naples and Sicily as the wife of King Ferdinand IV and III, who later became King of the Two Sicilies. As de facto ruler of her husband's kingdoms, Maria Carolina oversaw the promulgation of many reforms, including the revocation of the ban on Freemasonry, the enlargement of the navy under her favorite, Sir John Acton, and the expulsion of Spanish influence. She was a proponent of enlightened absolutism until the advent of the French Revolution, when, in order to prevent its ideas gaining currency, she made Naples a police state.