Saint Louise de Marillac was a French noblewoman born on August 12, 1591. She is best known for co-founding the Daughters of Charity with Saint Vincent de Paul. Louise dedicated her life to serving the poor and marginalized, emphasizing the importance of education and healthcare. In 1642, she was recognized for her contributions to social reform and the establishment of charitable organizations. Saint Louise de Marillac was canonized by Pope Pius XI in 1934, and her feast day is celebrated on March 15. She is the patron saint of social workers and those who care for the needy.