Marie-Madeleine Postel was a French Catholic nun and educator who lived from 1756 to 1846. Born Julie Françoise-Catherine Postel in Barfleur, she dedicated her life to religious service and teaching. During the French Revolution, she risked her safety by using her school to provide refuge for priests. She eventually established the Sisters of the Christian Schools, an order that grew significantly after she moved its headquarters to Saint-Sauveur-le-Vicomte. She is recognized as a saint in the Catholic Church for her heroic virtue and service.