There have been many saints over the centuries who have promoted devotion to the Sacred Heart of Jesus and the Immaculate Heart of Mary. Among them were St. Mechtilde in the 13th century and St. John Eudes in the 17th century.
St. John Eudes in particular did much to promote the devotion, including a revision of the following litany that was written by St. Mechtilde. It is a beautiful litany and invokes both the Sacred Heart of Jesus and the Immaculate Heart of Mary, seeing in them a single, united Heart.