The liturgical celebration of the Blessed Virgin Mary, Help of Christians, was instituted in 1814 by Pope Pius VII during a difficult time of the Church and for the end of his exile. St. Gaspar del Bufalo, who also returned to Rome at the same time after four years in exile, wished to have the Blessed Virgin Mary, Help of Christians as patron of his Congregation. He consecrated all his ministries to her and directed that her image be exposed for veneration during the missions, and that her feast be celebrated annually in the churches of the Congregation. St. Maria De Mattias also loved this devotion very much, as we read in the Rule of 1838 and in many of the letters addressed to her daughters.

Source: The Liturgy of the Hours, p.38.