Some Catholic calendars list Sunday June 18, 2000 as Trinity Sunday. What is the origin and meaning of this day?
John XXII (1316-1334) ordered this feast as a feast for the entire Church on the first Sunday after Pentecost. A new Office had been made by the Franciscan John Peckham, Canon of Lyons, later Archbishop of Canterbury (d. 1292). The feast ranked a double of the second class but it was raised to the category of primary of the first class on 24 July 1911 by Pius X (Acta Ap. Sedis III, 351). The Orthodox have no such feast as the practice is derived. Its origin is this: There was no doctrine or office in the early Church for the Trinity as it was not developed until 381 CE. The Sunday became mandatory from the Council of Laodicea (366) which proscribed the Sabbath and made Sunday the day of worship. This act was rejected along with the Trinity by the Sabbath-keeping Churches. The Unitarian Trinitarian Wars (see the paper The Unitarian/Trinitarian Wars (No. 268) saw entrenched conflict as the Roman Church established itself and became the origin of the Holy Roman Empire under Gregory I in 5
