Marie-Marguerite Dufrost de Lajemmerais was born at Varennes and educated by the Ursulines at Québec. About 1720 she came to Montréal where, in 1722, she married François d'Youville, by whom she had six children. Widowed in 1730, she devoted herself to raising her children, to religion, and to good works. She and three companions dedicated themselves to the service of the poor in 1737. Eighteen years later their order, the Sisters of Charity, received episcopal sanction. In 1747 Madame d'Youville took charge of the Hôpital général, which became a major part of her vocation.