Born on January 27, 1794, in Lavaltrie (Lower Canada), for fifty years Rosalie leads a life similar to that of most women of her time. On October 7, 1811, she marries Jean-Marie Jetté and has 11 children. She becomes a widow in 1832. Thirteen years after, freed of her family responsibilities, her life takes a new direction that will have lasting significance for the social and religious history of Montreal.
For five years, in the privacy of her home, she had been looking after a number of unwed mothers, with a broadmindedness rare for that period. At the same time, Bishop Bourget was convinced that, with Montreal becoming a large city, it was essential to help unwed mothers, rejected by their families and held in contempt by society. He therefore asks Rosalie to carry forward her charitable work by founding a religious community devoted to works of temporal and spiritual mercy. On May 1st, 1845, despite the opposition of her children, Rosalie goes to live with a “penitent” in the faubourg Saint-Laurent, on rue Saint-Simon, in a small house given for the new community by a rich citizen of Montreal and regular benefactor of Bishop Bourget’s charities.
On January 16, 1848, Rosalie and her collaborators make their religious profession. Once become Sister Marie of the Nativity, she refuses any position of authority in her community, since she deemed herself incapable of properly directing the organization during the period of development that lay ahead. Working in the backstage, she has a share in all the activities of the institute, including the reception of penitents, the care of new-born children at the “maternity room”, visiting the sick and the prisoners. In 1851 the community permanently settles in a mother house on Rue Campeau.
During the following years she is happy to see people shaking off their aversion to unwed mothers and recognizing the usefulness of her community. Finally, in 1859, she welcomes the founding of the secondary order of the Madeleines: the sisters of this order, recruited from among the penitents, are allowed to take religious vows and live within the community, obeying particular rules of dedication to contemplation. After five years of illness and isolation Rosalie dies on April 5, 1864.