Catherine de' Medici (1519-1589) was a Machiavellian politician, wife of Henry II of France, and later regent for her three feeble sons at the twilight of the Valois dynasty, who authorized the killing of French Protestants in the notorious Massacre of St. Bartholomew's Day in 1572.

Catherine de' Medici was never able to rule France as its monarch because the Salic Law restricted the succession solely to men. But this Machiavellian--whose father was Machiavelli's patron--ruled it as regent for nearly 30 years, and did everything she could to strengthen the position of her three weak sons on its throne. She presided over, and was partly responsible for, many of the horrors of the French Wars of Religion in the 1560s and 1570s, of which the worst was the massacre of Protestants gathered in Paris to witness the marriage of her daughter Marguerite Valois to Duke Henry of Navarre in 1572. Her...