36 Now, in the accomplishing of this work of redemption, the Blessed Virgin Mary was most closely associated with Christ; and so it is fitting to sing in the sacred liturgy: "Near the cross of Our Lord Jesus Christ there stood, sorrowful, the Blessed Mary, Queen of Heaven and Queen of the World." Hence, as the devout disciple of St. Anselm (Eadmer, ed.) wrote in the Middle Ages: "just as . . . God, by making all through His power, is Father and Lord of all, so the blessed Mary, by repairing all through her merits, is Mother and Queen of all; for God is the Lord of all things, because by His command He establishes each of them in its own nature, and Mary is the Queen of all things, because she restores each to its original dignity through the grace which she merited.
Source: Ad Caeli Reginam (Vatican.va)