Christ the King Sunday is one of the most modern additions to the liturgical calendar. It was first instituted by Pope Pius XI in 1925 to counter the growing secularism and nationalism in Europe at that time. Despite the Great War, dictatorships were on the rise again, and the Pope felt the need to implement a new solemnity, or major feast day, to reiterate the supremacy of Christ over all earthly rulers and powers.
Originally, this feast was not on the same date as it is now, but set as the last Sunday in October, such that it would always be observed on the Sunday before All Saints’ Day. In that original context, Christ the King Sunday was a precursor to the All Saints’ celebration, forming a sort of two-week festive time to honor our King and his court, so to speak.
In 1970 the Roman Catholics moved Christ the King Sunday to the end of “Ordinary Time”, the new name for Trinitytide in their radically reinvented liturgical calendar, upon which the Revised Common Lectionary is built (and thus the 1979 Prayer Book and the ACNA calendar today).
Traditionalists lament this decision: although the traditional last Sunday before Advent had a similar “feel” to Christ the King Sunday, the mood and tone was quite different. Where “Christ the King” is a joyful and triumphant and victorious sort of celebration, the last Sunday before Advent was a bit more solemn: Jesus is the Prophet and King long-awaited, who feeds his people and judges the nations and stirs us up to love and good works. It was explicitly a pre-Advent observance preparing the worshiper for the penitential weeks of Advent.
If you want to capture some of the purpose of the traditional calendar, which the Church used for 1,500 years before the 1970’s, consider re-imagining “Christ the King” as “Christ the Judge.” There is much to celebrate in both the old and new calendar and lessons, but also a powerful call to repentance and obedience to said King.