" the St Bartholomew’s Day Massacre, between 5,000 and 10,000 Protestants were slaughtered in less than twenty-four hours. When the pope in Rome heard the news from France, he was so overcome by joy that he organised festive prayers to celebrate the occasion and commissioned Giorgio Vasari to decorate one of the Vatican’s rooms with a fresco of the massacre (the room is currently off-limits to visitors).2 More Christians were killed by fellow Christians in those twenty-four hours than by the polytheistic Roman Empire throughout its entire existence. "

― Yuval Noah Harari , Sapiens: A Brief History of Humankind