athanasian, a.
Of or pertaining to Athanasius, bishop of Alexandria in the 4th century. [1913 Webster]
Athanasian creed, a formulary, confession, or exposition of faith, formerly supposed to have been drawn up by Athanasius; but this opinion is now rejected, and the composition is ascribed by some to Hilary, bishop of Arles (5th century). It is a summary of what was called the orthodox faith.