Tome of Leo

Leo's Tome refers to a letter sent by Pope Leo I to Flavian of Constantinople explaining the position of the Papacy in matters of Christology. The text confesses that Christ has two natures and was not of or from two natures. The letter was a topic of debate at the Council of Chalcedon in 451 and there was reaffirmed as a Catholic explanation of the Person of Christ. The letter was written in response to Flavian, Patriarch of Constantinople, who had excommunicated Eutyches, who also wrote to the Pope to appeal the excommunication.

Acknowledging the letter of Flavian that prompted the reply and the "proceedings of the bishops," the Pope declares that he now understands the controversy. He condemns Eutyches in the first paragraph, impugning the wayward presbyter's learning and misunderstanding of the Creed. Leo states that by the first three clauses of this Creed, "the engines of almost all heretics are shattered." Echoing the same, he recounts the Church's doctrine regarding the coeval nature of God the Father and God the Son. Bespeaking the necessity of the Incarnation, he next offers scriptural justification for the dogma and against the position of Eutyches, noting that the latter, for his own illumination on this matter, might have read relevant passages in Matthew, St. Paul's Epistle to the Romans, or Isaiah. Eutyches, the Pope says, believes Christ not to have been of our nature, but rather to have been the Word made flesh, i.e. to have taken a body that was created directly for the purpose, not a body truly derived from that of his Mother; in this Eutyches errs, for the Holy Ghost made the Virgin fertile, and from her body a real body was derived.

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