Among the many poor that Sister Rosalie Rendu (1786-1856), a Daughter of Charity of Saint-Vincent-de-Paul, attended to in the Mouffetard district of Paris, was a crippled old man, a militant atheist, who boasted of having taken part, during the winter of 1793-1794, in the appalling drownings organized to speed up the eradication of Catholics and priests clogging the prisons of Nantes.
Given his aggressive nature and the pride he took in his crimes, no one thought that he could be saved. Except for Sister Rosalie.
Sister Rosalie didn't proselytize or preach to him: she simply set an example of true, constant, and repeated charity. She simply gave the man a copy of the Miraculous Medal, which had just been revealed to Sister Catherine Labouré by Our Lady, in November 1830, in the chapel on the Rue du Bac in Paris.
Our Lady's intervention was discreet, but visible: the medal awakened in the old man a memory buried for over forty years and of which he had never spoken to anyone, in which Marian devotion was preeminent. He suddenly recalled Saint Louis-Marie Grignion de Montfort's canticle to Our Lady of Good Death:
"I put my trust, Virgin, in your help! Defend me, take care of my days, and when my last hour will come to determine my fate, allow me to die a most holy death", which he had once heard sung by Vendeans on their way to the scaffold.
In tears, the man whose heart used to be so hardened asked to return to Catholicism! He died shortly afterwards, devoutly, in the arms of Sister Rosalie, singing "his song" to the end.