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 response to the threatening atmosphere for Huguenots in these cities. In Rouen, where some hundreds were killed, the Huguenot community shrank from 16,500 to fewer than 3,000 mainly as a result of conversions and emigration to safer cities or countries. Some cities unaffected by the violence nevertheless witnessed a sharp decline in their Huguenot population. It has been claimed that the Huguenot community represented as much as 10% of the French population on the eve of the St. Bartholomew's Day massacre, declining to 7-8% by the end of the 16th century, and further after heavy persecution began once again during