By 1815, Rosalie was appointed the superior of the house on rue de l’Epee de Bois, becoming a beacon of hope in Paris's impoverished Mouffetard District and Faubourg Saint Marceau. Her fearlessness during the cholera epidemics of 1832, 1849, and 1854 elevated her status as a symbol of Christian Charity. Her famous 'visiting room' was a testament to her inclusive approach, welcoming everyone from priests to vagrants, and even notable figures like Charles X and Napoleon III. Rosalie was a guiding force for the newly formed Society of St. Vincent de Paul, offering invaluable advice and support. She was a woman of prayer, rising each morning at four to pray, a practice she believed enhanced her service. Rosalie's life, marked by moments of historic turmoil including the Reign of Terror and the Revolutions of 1830 and 1848, was a testament to her unflinching dedication.
Rosalie Rendu was an extraordinary woman whose fame had spread far and wide long before her death. When she passed away on February 9, 1856, an immense crowd estimated at 40,000-50,000 people from various social strata attended her funeral, a testament to the profound impact she had on society. She was beatified in 2003, a recognition of her heroic charity, elevating her to the altar and celebrating her extraordinary life of prayer and service.