Just What is Trinity Sunday?

While Pentecost (also known as Whitsunday) is a very well-known Christian festival, Trinity Sunday doesn't seem to be quite as well-known outside of the Anglican and Roman Catholic churches. Many denominations don't celebrate this festival. What is Trinity Sunday, and why does it have such an important place in the Christian calendar?

The doctrine of the Trinity during the fourth century was at the forefront of a major debate between competing versions of Christianity. Trinitarian belief had been a part of Christian belief since the time of the apostles. However, other groups had come into being that somehow taught different beliefs about the nature of God. Because these differing theologies had the potential to tear the Church apart, Christian leaders had to take a stand and define the triune nature of God. This lead to a stronger definition of the Trinity.

During this time, special propers honoring the Trinity were composed but not put into widespread usage. John Peckham, a monk who would later come the Archbishop of Canterbury created a special Office in honor of the Trinity in the late 13th century. In the 14th century, Pope John XXII designated a feast for the Trinity on the first Sunday after Pentecost. Prior to this, the Trinity had been honored either on this date or on the last Sunday before Advent.

In the Church Year, Trinity Sunday marks the start of the longest season known as Pentecost or Ordinary Time. Ordinary Time starts with Trinity Sunday and ends with the first Sunday before Advent, commonly known as Christ the King Sunday. In the Episcopal Church, there's a little bit of interesting trivia to pick up here. While the 1928 Book of Common Prayer was in usage, Sundays were counted as being after Trinity Sunday. Now, they're counted as being Sundays after Pentecost.

There aren't very many widely known customs associated with Trinity Sunday. Some decorate with pansies, also known as Trinity flowers because of the shape of their petals. In the Eastern Church, Trinity Sunday is synonymous with Pentecost. Not only do the clergy begin using green vestments again, but the churches are often decorated with greens on this day, going back to an old Slavic custom. Old Germanic superstitions often held the weather on Trinity Sunday to be of particular importance. In many provinces in the Anglican Communion, the creed of St. Athanasius (Quicunque Vult) is used in place of the Nicene Creed. Attributed to St. Athanasius but probably written after his death, this creed affirms that God is one, yet eternally present in three distinctly personal ways.

While unique Trinity Sunday customs are scarce, perhaps Christians of this age can create their own special customs that will be handed down. Instructing others about the Trinitarian symbols of the Church (sign of the cross, Trinity circle, etc.) can awaken a new interest in Christian symbolism. Since we're baptized in the Name of the Father, Son, and Holy Spirit, Trinity Sunday is a good day for us to consider what our baptismal covenant really means to us. There's one thing we can do, too, that is truly important on this day.

Like the Christians of the fourth century, we live in an age where our beliefs are often disputed. Many other religions, such as strict Judaism and Islam, treat Christianity as a polytheist faith because a triune God can't exist in their belief systems. Some groups that profess Christianity embrace polytheism, deny that Jesus is somehow God, or that the Persons of the Trinity are manifestations of Jesus operating in different times. In order to help others understand the Trinity, we need to understand why God has been revealed to us this way and how we can best explain it to others.

Trinity Sunday honors God in all His fullness. May we all come to appreciate the value of this holiday.