Holy Trinity Sunday is celebrated on the first Sunday following Pentecost in most of the liturgical churches in Western Christianity. It is a solemn celebration of the belief in the revelation of one God, yet three divine persons. It was not uniquely celebrated in the early church, but as with many things the advent of new, sometime heretical, thinking often gives the Church a moment in which to explain and celebrate its own traditions; things it already believes and holds dear. In the early 4^th century when the Arian heresy was spreading, the early church, recognizing the inherent Christological and Trinitarian implications, prepared an Office of Prayer with canticles, responses, a preface, and hymns, to be recited on Sundays to proclaim the Holy Trinity. Pope John XXII (14^th century) instituted the celebration for the entire Church as a feast; the celebration became a solemnity after the liturgical reforms of Vatican II. Continue reading →