John was the son of Zebedee the fisherman and Salome the daughter of Joseph, the betrothed of the Holy Mother of God. Called by the Lord Jesus, John immediately left his father and the fishing nets and followed Christ with his brother James. From that time, he was not parted from his Lord until the end. With Peter and James, he was present at the raising of Jairus's daughter and at the Lord's Transfiguration (Metamorphosis), and he laid his head on Jesus' breast at the Mystical Supper.

On this day are celebrated God's mercy, His wondrous act and His wisdom: His mercy towards the devout and righteous parents of Saint John, the aged Zacharias and Elizabeth, who had all their lives begged a child of God; the miracle (wonder or in Greek, θαύμα (thavma)) of the conception of John in Elizabeth's more-than-aged womb; and the wisdom of the dispensation of man's salvation. For John, God had especially great plans: that he should be a Prophet and the Forerunner of Christ the Lord, the Savior of the world.

While sharing many traditions, East and West in Christianity began to diverge from each other from an early date. Whereas the basilica, a long aisled hall with an apse at one end, was the most common form in the West, a more centralized style became predominant in the East. These churches were in origin 'martyria' focused on the tombs of the Saints--specifically, the Martyrs who had died during the persecutions, which only fully ended with the conversion of Emperor Constantine. They copied pagan tombs and were roofed over by a dome which symbolized heaven.