Paris in the 16th century Wars of Religion (1562-1598). Paris was the stronghold of the Catholic League. On the night of August 23–24, 1572, while many prominent Protestants from all over France were in Paris on the occasion of the marriage of Henri of Navarre—the future Henry IV—to Margaret of Valois, sister of Charles IX, the royal council decided to assassinate the leaders of the Protestants. The targeted killings quickly turned into a general slaughter of Protestants by Catholic mobs, known as St. Bartholomew's Day massacre, and continued through August and September, spreading from Paris to the rest of the country. About three thousand Protestants
St. Bartholomew's Day massacre 18th-century historian Louis-Pierre Anquetil, in his "Esprit de la Ligue" of 1767, was among the first to begin impartial historical investigation, emphasizing the lack of premeditation (before the attempt on Coligny) in the massacre and that Catholic mob violence had a history of uncontrollable escalation. By this period the Massacre was being widely used by Voltaire (in his "Henriade") and other Enlightenment writers in polemics against organized religion in general. The question of whether the massacre had long been premeditated was not entirely settled until the late 19th century; Lord Acton changed his mind on the matter twice, finally concluding