The Saint Bartholomew's Day massacre in 1572 was a targeted group of assassinations and a wave of Catholic mob violence directed against the Huguenots during the French Wars of Religion. Traditionally believed to have been instigated by Queen Catherine de' Medici, the mother of King Charles IX, the massacre started a few days after the marriage on 18 August of the king's sister Margaret to the Protestant King Henry III of Navarre. Many of the wealthiest and most prominent Huguenots had gathered in largely Catholic Paris to attend the wedding.