In the late 16th-century French Wars of Religion, Paris was a stronghold of the Catholic League, the organisers of 24 August 1572 St. Bartholomew's Day massacre in which thousands of French Protestants were killed. The conflicts ended when pretender to the throne Henry IV, after converting to Catholicism to gain entry to the capital, entered the city in 1594 to claim the crown of France. This king made several improvements to the capital during his reign: he completed the construction of Paris's first uncovered, sidewalk-lined bridge, the Pont Neuf, built a Louvre extension connecting it to the Tuileries Palace, and created the first Paris residential square, the Place Royale, now Place des Vosges. In spite of Henry IV's efforts to improve city circulation, the narrowness of Paris's streets was a contributing factor in his assassination near Les Halles marketplace in 1610.