[The iconoclasts] have separated themselves from the body of Christ, and from the chief throne in which Christ placed the keys of faith: against which the gates of hell, namely the mouths of heretics, have not prevailed up to now, nor shall they ever prevail, according to the promise of him who does not lie. Therefore let the most blessed and apostolic [Pope] Paschal, who is worthy of his name, rejoice, for he has fulfilled the work of Peter.
Letter of Saint Theodore the Studite to Pope Paschal I.
