St. Louise de Marillac (1591-1660) was a great friend and valuable collaborator of Vincent de Paul and co-founded the Daughters of Charity with him.
Louise was born in Paris in 1591. She was raised by her father, the aristocratic Louis de Marillac. She attended boarding school at a Dominican convent where she received a classical education befitting a member of the upper class. After her father’s death, limited resources required that she live in a boarding house where she learned domestic, organizational, and medical skills.
Louise married Antoine le Gras, secretary to the Queen Mother of France. Her social status allowed her to travel and to mingle with members of the ruling and upper-class, but she was equally comfortable with the poor, especially in her role with the Ladies of Charity. Antoine died in 1625.
In 1629, Vincent de Paul invited Louise to work with him in guiding the Confraternities of Charity in France. Her work gave her firsthand knowledge of the plight of the poor. Her life experience helped her develop the structures needed to secure ongoing service to the poor. In 1633, she began to invite young women to join her in serving the poor and live in community. This evolved into the Daughters of Charity.
Louise died on March 15, 1660, and was canonized in 1934. Pope John XXIII declared her Patroness of Christian Social Workers. Her feast day is celebrated on May 9.
(https://famvin.org/wiki/Louise_de_Marillac)