Saitn John Bosco had a vision of the Two Columns, and recommended two devotions, that to the Blessed Sacrament and to the Blessed Virgin Mary under the title of Help of Christians.
He also composed a short prayer to the Blessed Virgin under this title;
(#379 in the Raccolta): Mary, powerful Virgin, Thou art the mighty and glorious protector of holy Church; thou art the marvelous help of Christians; thou art terrible as an army in battle array; thou alone hast destroyed every heresy in the whole world. In the midst of our anguish, our struggles and our distress defend us from the power of the enemy and at he hour of our death receive our souls in paradise. Amen.
Novena said before her Feast on May 24th (May 15th is the time to begin.)
