Though it can never been known for sure, given the dating of the seal, this Kallistos could have been the Kallistos who was one of the 42 Martyrs of Amorium (Greek: οἰ ἅγιοι μβ′ μάρτυρες τοῦ Ἀμορίου) who were a group of
Byzantine senior officials taken prisoner by the Abbasid Caliphate in the Sack of Amorium in 838 and executed in 845, after refusing to convert to Islam. They are commemorated by the Eastern Orthodox
Church on March 6. Pogh_poor