47 Since we are convinced, after long and serious reflection, that great good will accrue to the Church if this solidly established truth shines forth more clearly to all, like a luminous lamp raised aloft, by Our Apostolic authority We decree and establish the feast of Mary's Queenship, which is to be celebrated every year in the whole world on the 31st of May. We likewise ordain that on the same day the consecration of the human race to the Immaculate Heart of the Blessed Virgin Mary be renewed, cherishing the hope that through such consecration a new era may begin, joyous in Christian peace and in the triumph of religion.
Source: Ad Caeli Reginam (Vatican.va)