Mission and Confession
The sources present Theodore and Theophanes as emissaries of the Church of Jerusalem to the imperial capital, charged with defending the legitimacy of icon veneration. OrthodoxWiki relates that when Leo V revived iconoclasm in 813, Theodore was sent to dissuade the emperor and was scourged and exiled for his pains. The brothers continued their resistance through the reigns of Michael II and Theophilus, and by tradition were moved between places of confinement, including, by one account, a monastery at Sosthenes on the Bosphorus.
The synaxarion preserves an exchange in which Theodore, offered his freedom in return for a single act of communion with the iconoclasts, refused outright; the tradition records that he likened such a momentary compromise to consenting to be beheaded for only a short time. His steadfastness through repeated exile and imprisonment is the reason the Church remembers him as a confessor.