St. John Eudes was a founder of the French School of Spirituality which advocated a strong, personal relationship with Jesus Christ, an important role for Mary as the mother who permitted his entry into the world and a deep, interior prayer life. He founded an association of diocesan priests who live as vowed religious and promote vocations to the priesthood and the formation of priestly candidates. They also preach missions and teach at the college level.
St. John is perhaps best known for his promotion of devotion to the Immaculate Heart of Mary and the Sacred Heart of Jesus. We do not think it is odd to see images of Jesus' and Mary's disembodied hearts, but these images presented no small obstacle to the spread of the devotion.
Most Sacred Heart of Jesus, Have mercy on us!