The first Sunday after Pentecost, instituted to honor the Most Holy Trinity. The early Church did not honor the Trinity by a special Office or day. When the Arian heresy was at its height, an Office with canticle, responses, a Preface, and hymns was composed by the Fathers, and recited on Sundays. Bishop Stephen of Liege, 903–920, wrote an Office of the Holy Trinity which was recited in some places on the Sunday after Pentecost, in others on the Sunday preceding Advent. Saint Thomas Becket, consecrated Archbishop of Canterbury on the Sunday following Pentecost, obtained for England the privilege of honoring the Holy Trinity on that day, and Pope John XXII (1316–1334) made this practise universal. A Plenary Indulgence is gained by those who receive the Holy Eucharist on this day. The Gospel of the Mass is the charge of Christ to His Apostles to teach all nations “baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.” It is the last day in the United States for the observance of what is known as the Easter duty, so called because it is of obligation for all Catholics to confess and partake of Holy Comnlunion once a year, usually between the first Sunday of Lent and Trinity Sunday.
- “Trinity Sunday”. . CatholicSaints.Info. 30 May 2015. Web. 27 March 2017. <>