Preach from My Psalter

According to the account of the Blessed Alain de la Roche, the Holy Mother of God appeared to Saint Dominic in 1214 after he had spent three days and nights in continual prayer and penance in a forest near Toulouse. The Virgin said to him: "Do you know which weapon the Holy Trinity has used to reform the world?" "O my Lady," answered Saint Dominic, "you know it far better than I do, because next to your Son Jesus Christ you have always been the chief instrument of our salvation." Then our Lady replied, "I want you to know that the principal weapon has always been the Angelic Psalter, which is the foundation-stone of the New Testament. Therefore, if you want to win these hardened hearts for the Lord, preach from my Psalter." This is the way the most Holy Rosary of Mary came into being, which Saint Dominic used forthwith against the Albigensian heresy. Queen Blanche of Castile immediately adopted this new form of devotion, to which she attributed the birth of her son Saint Louis King of France.