EUSEBIUS OF THESSALONICA : Bishop of Thessalonica c. 600. He wrote a polemic work in ten books against one Andrew, a monk belonging to the Aphthartodocetæ. That the Eusebius to whom Photius (Bibliotheca, codex clxii.) ascribes the work was Eusebius of Thessalonica is clearly shown by one of a number of letters which Gregory the Great wrote to this Eusebius (Epist.. xi. 55 ).