Catharism was the most successful heresy of the Middle Ages. Flourishing principally in the Languedoc and Italy, the Cathars taught that the world is evil and must be transcended through a simple life of prayer, work, fasting and nonviolence. They believed themselves to be the heirs of the true form of Christianity going back to the Apostles and the Gnostics. Alarmed at the success of Catharism, the Church launched the Albigensian Crusade to exterminate the heresy. While previous Crusades had been directed against Muslims in the Middle East or pagans in the Baltic, the Albigensian Crusade was the first Crusade to be directed against fellow Christians, and also the first European genocide. With the fall of the Cathar fortress of Montsé gur in 1244 and Sirmione in 1276, Catharism was largely obliterated. But the Church was never able to completely eradicate the myth of the Cathars, and the heresy became a powerful symbol for 19th century Languedocian separatists, the German archaeologist Otto Rahn, and the philosopher Simone Weil. Today, the mystique surrounding the Cathars is as strong as ever.