Abstract
The letter from Arius to Alexander of Alexandria, also known as «Arius’ profession of faith», has been transmitted in its original language, Greek, by Athanasius (De Synodis) and Epiphanius (Panarion). Also, Hilary of Poitiers quotes a Latin translation of the letter twice (De Trinitate IV and VI). The comparative study of the two Greek versions and the Latin translation reveals small textual variants, which points to the independence of the three testimonies. The textual variant (κτιστὴν, instead of κριτὴν) is the most interesting; it comes from a Greek version that has not been preserved. However, our work has been able to reconstruct this lost textual variant using an ancient and forgotten conjecture of Erich Klostermann.