Although attributed to Athanasius, the Athanasian Creed (Symbolum Quicunque) was originally written in Latin sometime in the 6th century, possibly in France, and by the 9th century it was used in the liturgy. In the Western Church, the Athanasian Creed is the last of the three great ecumenical creeds (along with the Apostles' and the Nicene). The Eastern Church does not use either the Apostles' or the Athanasian Creed. The only true ecumencial creed in all Christendom is the Nicene Creed.
While not Athanasian in authorship, it is Athanasian (and Augustinian) in doctrine, especially emphasizing his defence of the Nicene Creed and the deity of Jesus Christ. The creed's strong trinitarian confession makes it an obvious choice for Trinity Sunday. Since the 1960s, the use of the Athanasian Creed has declined to its sole use on Trinity Sunday, however, in the 19th century, Lutheran churches were apt to use the creed more often throughout the liturgical year.
The Creed confesses two main doctrines: the holy Trinity and the two natures of Christ. In doing so, the Creed neatly summarizes the orthodox councils and synods of the first four centuries.Sadly, too many Lutherans seem to just roll their eyes and groan when we confess this Creed on Trinity Sunday. The Creed, however, is not going anywhere: it's in our hymnals and in the Book of Concord. We should follow the exhortation of the collect to read, mark, learn, and inwardly digest what the Creed teaches about the holy Trinity and the two natures of Christ. Luther considered the Athanasian Creed as the queen of the creeds in the Church, and so should we.