Catherine I, also Catherine of Courtenay, was the recognised Latin Empress of Constantinople from 1283 to 1307, although she lived in exile and only held authority over Crusader States in Greece. In 1301, she became the second wife of Charles of Valois, by whom she had one son and three daughters; the eldest of these, Catherine II of Valois, Princess of Achaea succeeded her as titular empress.

Charles of Valois, the fourth son of King Philip III of France and Isabella of Aragon, was a member of the House of Capet and founder of the House of Valois, whose rule over France would start in 1328.