Bl. Bartolo Longo, who wrote the prayer, is an unlikely hero of the Church. Not only was he a lawyer, he was also ordained as a priest in a satanic cult.
Eventually, he lost his wits, regained them enough to reconcile with the Church and become a Dominican tertiary, then handed them over once and for all to the Blessed Virgin and the apostolate of the Holy Rosary. He established the Shrine (now a basilica) of Our Lady of the Most Holy Rosary in Pompeii, and promoted the Rosary for the last five decades of his life, following the inspiration, "Whoever spreads the Rosary is saved!"
The blessed John Paul II referred to him several times in his Apostolic Letter Rosarium Virginis Mariae, even concluding the letter with a quotation from the Supplication:
O Blessed Rosary of Mary, Sweet chain which unites us to God, Bond of love which unites us to the angels, Tower of salvation against the assaults of Hell, Safe port in our universal shipwreck, We will never abandon you. You will be our comfort in the hour of death: Yours our final kiss as life ebbs away.
And the last word from our lips will be your sweet name, O Queen of the Rosary of Pompei, O dearest Mother, O Refuge of Sinners, O Sovereign Consoler of the Afflicted. May you be everywhere blessed, Today and always, On earth and in heaven.