The Vatican announced last week that the Church will celebrate the Blessed Virgin Mary in her
role as “Mother of the Church” every year on the Monday after Pentecost — May 21st this year — as a way to foster Marian piety and the maternal sense of the Church.
Cardinal Robert Sarah explained that Pope Francis added the memorial to the Roman Calendar in order to promote a greater devotion to the Blessed Virgin Mary under this particular title, and encourage growth in “the maternal sense of the Church” and in “genuine Marian piety.”
That comes as good news to all Viatorians, who have a strong devotion to Mary, instilled in them by their founder, Fr. Louis Querbes.
The Our Lady of Grace statue at St. Nizier Church in Lyon, France
Back in the 19th century, Fr. Querbes fostered a special devotion to Mary during the month of May, as the newly installed pastor of St. Nizier Church in Lyons, France.
He would assemble his students before the shrine of Our Lady of Grace, located on a side altar in the church, where they would sing songs and recite prayers to the Blessed Mother.
Before long, this “Month of Mary” spread to all of the Catholic churches in France.
In recognition of Fr. Querbes’ role, Cardinal Pierre-Marie Gerlier dedicated a plaque in 1952, near the shrine of Our Lady of Grace, that reads: “To the memory of Fr. Louis Querbes (1793-1859), curate of the parish of St. Nizier, later pastor of Vourles and founder of the Clerics of St. Viator, who in 1816, before this altar, with the pupils of his parish about him, began a practice which soon spread to every part of France — the Devotion of the Month of Mary.” 
Fr. Querbes and his special devotion was captured in a book about his life, published in 1955, appropriately called, “The Mary-Hearted Catechist.”