Mentioned in a fragment of a manuscript from the 14th century, which was kept in the Gymnasium of Serres. He was a Bishop in Belesos. There is a written record on a fragment of a manuscript from the Gymnasium of Serres, that indicates the existence of a Bishop in Belesos (Veles) named Athanasios (ὁ Βελεσοῦ Ἀθανάσιος).