St. Leonard of Port Maurice, the celebrated missionary, had the Three Hail Marys recited morning and evening in honor of Mary Immaculate, to obtain the grace of avoiding all mortal sins during the day or night; moreover he promised in a special manner eternal salvation to all those who proved constantly faithful to this practice. He gave this devotion of Three Hail Marys as a penance in the confessional, especially for those who were struggling with sins of impurity.

Practice: Recite morning and evening, three Hail Marys in honor of the three great privileges bestowed upon Our Blessed Mother by the most Blessed Trinity with this invocation at the end: for the morning: "O my Mother preserve me from mortal sin during this day." For the evening: "O my Mother preserve me from mortal sin during this night."

(Pope St. Pius X gave his Apostolic Blessing to this practice and the devotion was raised to an Archconfraternity by Pope Benedict XV.)