John III of Antioch

John of Antioch (; , Yūḥannā), also known by the epithet Polites (, literally "the Citizen"), was the Chalcedonian Patriarch of Antioch from 4 October 996 until his death in July 1021. Before his elevation to the patriarchate, he served as the chartophylax of the Hagia Sophia in Constantinople.

Early life and career John's epithet "Polites" suggests he was a native of Constantinople. In one instance, the two arranged to meet at Dorylaion but missed each other because John arrived too early.

During his tenure, John corresponded with various church figures. He is the author of canonical responses concerning baptism (Responsa de baptismo) addressed to Theodoros, the Metropolitan of Ephesus, which some scholars suggest he may have written while still chartophylax in Constantinople. He also received letters from Philetos of Synada, who interceded with John on behalf of an exiled man named Thomas and urged John to petition the dux of Antioch, Nikephoros Ouranos, for a pardon following the latter's military victory around 1005/1006.

John was also involved in inter-patriarchal relations. According to the Georgian author Ephrem Mtsire, John transferred the Patriarchate of Antioch's claim to the financial contributions of the Georgian Church for the consecration of myron to the Patriarchate of Jerusalem under Orestes, an event that likely occurred around 1000 when Orestes traveled through Antioch to Constantinople. Furthermore, the Syriac chronicler Michael the Syrian notes that the Chalcedonian Patriarch of Antioch held the Jacobite Patriarch Athanasios in high regard, a reference generally attributed to John.

Death and legacy John died after a patriarchate lasting twenty-four years and nine months, placing his death in July 1021.