At the end of the 12th century, Saint Dominic of Guzman was deeply grieved to see that the gravity of people's sins was preventing the conversion of the Albigensians. He decided to retire into the forest alone to pray. He spent three days and three nights in prayer, doing penance, and flagellating himself until he actually lost consciousness. At that moment, the Blessed Mother appeared to him with three angels and said that the best weapon for converting hardened souls was not flagellation, but the prayer of her Psalter. Saint Dominic then went to the Cathedral of Toulouse; the bells rang and people gathered to listen to him. When Dominic began speaking, a fierce storm with claps of thunder and strong winds broke out and frightened the people. Everybody present saw the image of the Blessed Virgin Mary on the cathedral; the Virgin raised her arms three times to heaven. Saint Dominic began to pray the Psalter of the Blessed Virgin Mary and the storm ended. On another occasion Saint Dominic was meant to preach in Notre Dame Cathedral in Paris on the feast of Saint John. While he was praying the rosary before mass, the Blessed Virgin appeared and said to him that his homily was quite good, but that it would be better to change it and she gave him a book with images, in which she explained how much the rosary pleased God, because it reminded him of the moment when humanity, represented by Mary, had accepted his Son as the Savior.