St. Bartholomew's Day massacre

The St. Bartholomew's Day massacre (Massacre de la Saint-Barthélemy in French) in 1572 was a targeted group of assassinations, followed by a wave of Catholic mob violence, both directed against the Huguenots (French Calvinist Protestants), during the French Wars of Religion. Traditionally believed to have been instigated by Catherine de' Medici, the mother of King Charles IX, the massacre took place five days after the wedding of the king's sister Margaret to the Protestant Henry III of Navarre (the future Henry IV of France). This marriage was an occasion for which many of the most wealthy and prominent Huguenots had gathered in largely Catholic Paris.

• http://en.wikipedia.org/wiki/St. Bartholomew's Day massacre