The Athanasian Creed, also known as Pseudo-Athanasian Creed or Quicunque Vult (also Quicumque Vult), is a Christian statement of belief focused on Trinitarian doctrine and Christology. The Latin name of the creed, Quicunque vult, is taken from the opening words, “Whosoever wishes”. The creed has been used by Christian churches since the sixth century. It is the first creed in which the equality of the three persons of the Trinity is explicitly stated. It differs from the Nicene-Constantinopolitan and Apostles’ Creeds in the inclusion of anathemas, or condemnations of those who disagree with the creed (like the original Nicene Creed).
Widely accepted among Western Christians, including the Roman Catholic Church and some Anglican churches, Lutheran churches (it is considered part of Lutheran confessions in the Book of Concord) and ancient, liturgical churches generally, the Athanasian Creed has been used in public worship less and less frequently.
It was designed to distinguish Nicene Christianity from the heresy of Arianism. Liturgically, this Creed was recited at the Sunday Office of Prime in the Western Church; it is not in common use in the Eastern Church. The creed has never gained acceptance in liturgy among Eastern Christians since it was considered as one of many unorthodox fabrications that contained the Filioque clause. Today, the Athanasian Creed is rarely used even in the Western Church. When used, one common practice is to use it once a year on Trinity Sunday.