Saint Pierre Fourier (1565–1640) was a French priest, canon regular, and social reformer known as the 'Good Father of Mattaincourt' for his dedication to revitalizing his parish and co-founding the Congregation of Notre-Dame, an order of teaching sisters dedicated to the free education of poor girls. He was a strong proponent of the Catholic Reformation, using clear preaching and a holy example to counter Calvinism in the region. He successfully brought the majority of the population in the Principality of Salm back to the Catholic faith within six months of his mission there. Due to his loyalty to the Duchy of Lorraine during the Thirty Years' War, he was forced into exile in Gray, where he died in 1640. He was canonized as a saint by Pope Leo XIII in 1897. St. Pierre Fourier is remembered for his deep piety, ascetic lifestyle, intellectual rigor (he knew the Summa Theologica of St. Thomas Aquinas by heart), and immense.