Our Sovereign Pontiff Pius IX., at the prayer of several devout persons, vouchsafed to grant, by a Rescript of the Segretaria of the Memorials, dated May 19, 1854 -
The indulgence of fifty days, every time that, with contrite heart, the following prayer is said to the most holy Virgin, extracted from the eighteenth Sermon of St. Augustine, De Sanctis.
O Beata Virgo Maria! quis tibi digne valeat jam gratiarum, ac laudum praeconia rependere, quae singulari tuo assensu mundo succurristi perdito? Quas tibi laudes fragilitas humani generis persolvat, quae solo tuo commmercio recuperandi aditum invenit? Accipe itaque quascumque exiles, quascunque meritis tuis impares, gratiarum actiones, et cum susceperis vota, culpas nostras orando excusa. Admitte nostras preces intra sacrarium exauditionis, et reporta nobis antidotum reconciliationis. Sit per te excusabile, quod per te ingerimus, fiat impetrabile quod fida mente poscimus. Accipe quod offerimus, redona quod rogamus, excusa quod timemus, quia tu es spes unica peccatorum. Per te speramus veniam delictorum, et in te, beatissima, nostrorum est expectatio praemiorum. Sancta Maria, succurre miseris, juva pusillanimes, refove flebiles, ora pro populo, interveni pro clero, intercede pro devoto femineo sexu; sentiant omnes tuum juvamen quicumque celebrant tuam sanctam Commemorationem. Assiste parata votis poscentium, et reporta nobis optatum effectum. Sint tibi studia assidua orare pro populo Dei, quae meruisti, benedicta, Redemptorem ferre mundi, qui vivit et regnat in saecula saeculomum. Amen.
Mary, Virgin ever-blessed! who can worthily praise thee or give thanks to thee, who, by the assent of thy will alone hast rescued a fallen world? What honours can the weakness of our human nature pay to thee, which by thy intervention alone hath found the way to restoration? Accept, then, such poor thanks as we have here to offer, though they are unequal to thy merits, and receiving our vows, obtain by thy prayers the remission of our offences. Admit thou our prayers into the sanctuary of the heavenly audience, and bring back to us the medicine of our reconciliation. Through thee may that be pardonable which through thee we bring before God; and that be admissible which we ask with faithful heart. Accept what we offer, grant us what we ask, pardon us what we fear; for thou art the sole hope of sinners. Through thee we hope for the forgiveness of our faults; and in thee, most blessed one, is the hope of our reward. Holy Mary, succour the wretched, help the faint-hearted, comfort the sorrowful, pray for the people, shield the clergy, intercede for the devout female sex, let all feel thy help who celebrate thy holy commemoration. Be thou at hand, ready to aid our prayers, when we pray; and bring back to us their desired result. Make it thy care, blessed one, to intercede ever for the people of God - thou who didst deserve to bear the Redeemer of the world, who liveth and reigneth for ever and ever. Amen.
From the Raccolta. http://www.liturgialatina.org/raccolta/mary.htm