13 Soon will be celebrated the annual solemnities of Christ the King, Whose reign and Whose peace We have heralded and prayed for from the outset of Our pontificate. It seems to Us that it will be timely to prepare for the Feast by solemn tridua in the parish churches, whereby to implore from the God of Mercies celestial counsels and the gifts of peace. In pledge thereof We send to you, Venerable Brethren, as well as to all who shall respond to Our appeal, the Apostolic Blessing.
Source: Nova Impendet (Vatican.va)