He was a monk who lived a solitary life in the desert until he was consecrated Pope and Patriarch of Alexandria on 29 May 505.
He was a contemporary of the Roman Emperor Anastasius I, who favoured the non-Chalcedonian churches, and of Severus of Antioch, the champion of Miaphysitism in Syria.
The latter wrote a message to John regarding the nature of Christ, which reads: Jesus Christ, after the union with flesh, has become of one Nature with one Will without separation, and I believe in the same faith of Pope Cyril and Pope Dioscorus.John replied with a message that testified to the union of the essence of God, and the trinity of His characters.
He also proclaimed that by the incarnation of the eternal Son of God, the Divine and the human nature have become one and no longer two natures, without separation, mingling, or confusion.
He said that the Orthodox faith was to profess that God the word suffered by the flesh with which he was united.