5 Now these things so auspiciously and happily begun as we taught in Our Encyclical Letter "Quas primas," we Ourselves, consenting to very many long-continued desires and prayers of Bishops and people, brought to completion and perfected, by God's grace, when at the close of the Jubilee Year, We instituted the Feast of Christ the King of All, to be solemnly celebrated throughout the whole Christian world. Now when we did this, not only did we set in a clear light that supreme sovereignty which Christ holds over the whole universe, over civil and domestic society, and over individual men, but at the same time we anticipated the joys of that most auspicious day, whereon the whole world will gladly and willingly render obedience to the most sweet lordship of Christ the King. For this reason, We decreed at the same time that this same Consecration should be renewed every year on the occasion of that appointed festal day, so that the fruit of this same Consecration might be obtained more certainly and more abundantly, and all peoples might be joined together in Christian charity and in the reconciliation of peace, in the Heart of the King of kings and Lord of lords.
Source: Miserentissimus Redemptor (Vatican.va)