The Feast of Christ the King was established by Pope Pius XI in 1925 as an antidote to secularism, a way of life which leaves God out of man’s thinking and living and organizes his life as if God did not exist. The feast is intended to proclaim in a striking and effective manner Christ’s royalty over individuals, families, society, governments, and nations. Pius took as his motto ‘Christ’s peace in Christ’s kingdom’, interpreting it as meaning that the church and Christianity should be active in, and not insulated from, society. 
On 11 December 1925, Pope Pius XI promulgated his encyclical letter Quas primas, on the Kingship of Christ. The encyclical dealt with what the Pope described correctly as “the chief cause of the difficulties under which mankind was labouring.” He explained that the manifold evils in the world are due to the fact that the majority of men have thrust Jesus Christ and His holy law out of their lives; that Our Lord and His holy law have no place either in private life or in politics; and, as long as individuals and states refuse to submit to the rule of our Saviour, there will be no hope of lasting peace among nations. Men must look for the peace of Christ in the Kingdom of Christ—Pax Christi in Regno Christi.

Christ the King!

Pope Pius XI: 1876-1958

Why did the Holy Father want to commemorate, by a special feast, a doctrine so uncontroversial? Why was the moment ripe for that particular lesson?

When he was crowned Pope, he insisted on giving his blessing to the world from the balcony of St. Peter’s, a thing no Pope had done since the loss of its temporal power. Even so early, he had made up his mind that the Papacy must come out of its retirement, and make itself felt as a moral force in the world. And he introduced this feast of the Kingship of Christ with the same ideal in view. He saw that the minds of men, of young men especially, all over Europe, would be caught by a wave of conflicting loyalties which would drown the voice of conscience and produce everywhere unscrupulous wars between nations.

The institution of this feast was not a gesture of clericalism against anti-clericalism, still less a gesture of authoritarianism against democracy. It was a gesture of Christian truth against a world which was on the point of going mad with political propaganda; it was to say to the world that the claim of the divine law upon the human conscience comes before anything else.