In the year 1162, the Norman Archbishop of Canterbury Theobald of Bec died, and the time came to elect his successor. It was almost universally understood that the proper choice would be an Englishman, and the man elected was a clerk in Theobald’s household by the name of Thomas Becket. Becket, being a deacon at the time of his election, was ordained to the priesthood on the Saturday following the Feast of Pentecost and the next day, was consecrated bishop. In a sparse number of places in England at that time, the first Sunday following Pentecost (or Whitsunday as it was then called) was observed as the Feast of the Most Holy Trinity. Thomas, we are told, on that day in 1162, was not only made a Bishop, but was converted from an ambitious ecclesiastic to a Saint! Due to his devotion to the Trinity, he decreed that that Sunday be celebrated universally in the English Church as a day dedicated to the Trinity, and ever since, it has been kept as Trinity Sunday. In the 14th Century, a papal decree made the practice universal in the Western Church.
At the time of the Reformation, a successor to Thomas, Archbishop Thomas Cranmer, was certain to keep this day on his calendar in the Book of Common Prayer, with the collect:
“Almighty and everlasting God, which hast given unto us thy servants grace by the confession of a true faith to acknowledge the glory of the eternal Trinity, and in the power of the divine majesty to worship the unity: we beseech thee, that through the steadfastness of this faith, we may evermore be defended from all adversity, which livest and reignest, one God, world without end.”
It was understood also that on this day, the Creed of Saint Athanasius would be recited. Though not a product of Saint Athanasius himself, this particular creed has always been one of the three creeds which Anglicans accept. In 1662, the rubrics surrounding the use of creeds in the liturgy commended the Apostles’ Creed for use at Morning and Evening Prayer. But, it also required that the Athanasian Creed be sung or said on the following days: Christmas Day, the Epiphany, Saint Matthias Day, Ascension Day, and the Feasts of Saint John the Baptist, Saint James, Saint Bartholomew, Saints Simon and Jude, and Saint Andrew, as well as Trinity Sunday. This was, to say the least, troublesome to the Puritans, many of whom desired to see the Athanasian Creed be fully reformed, especially due to their hesitance to say that belief was necessary in order to be saved. Some, especially Latitudinarians, said that the recitation of Athanasian Creed was unpopular, difficult to understand, and both unedifying and difficult to recite for normal congregations. But, as in many things, the wisdom of the Prayerbook has ultimately prevailed.
As we are taught in the Catechism, “the purpose of the Creeds is to declare and safeguard God’s truth about himself, ourselves, and creation, as God has revealed it in Holy Scripture.” That is to say that, for Anglicans, the doctrine of the Trinity is not an extra-biblical addition to the Christian Tradition, but at the heart of Divine Revelation, God revealing himself in three distinct persons, the Father, the Son, and the Holy Spirit. The Trinitarian affirmations are made following the right meditation upon God in Christ and the presence of His Holy Spirit in the Church. The doctrine of the Trinity is articulated in the Athanasian Creed, not only to teach us what that faith of the ancient Church is, but also to keep it safe from error. The Church continues to hold this faith.