Theodore Hatzis was a new-martyr of Mytilene (Lesbos) who suffered under Ottoman rule in 1784. According to the synaxarion, he was born in the city of Mytilene, where he married and raised children in Orthodox piety. At some point he renounced Christ and accepted Islam, but he soon repented of his denial and, leaving his family behind, withdrew to Mount Athos.
The tradition relates that even in the monastery Theodore remained deeply anguished over his apostasy. Seeking to atone for it, he returned to confess the Orthodox faith openly before a Muslim judge in the year 1784. The judge, enraged, ordered him to be severely tortured; he was then strangled with a rope and his body cast into the sea. Christians afterward recovered his remains and buried them in a church dedicated to Saint John the Baptist.
Theodore belongs to the broad company of New Martyrs who, during the centuries of Ottoman domination, confessed Christ at the cost of their lives, many of them after a prior lapse into Islam followed by public repentance. His principal commemoration falls on January 30, while a separate observance on September 4 marks the uncovering of his relics in 1967.