Christians have given John the Apostle many names and attributed many books of the Bible to him. The different names refers to different aspects of his personality and different books attributed to him. The names emphasize those aspects in the mind of the listener. The names are often used in icons. Some historians consider the books attributed to John to have been written by more than one person, none of them John the Apostle (see John the Presbyter, John of Patmos, authorship of Johannine literature).
According to some Christian traditions, the four evangelists are connected to the four living creatures of the Apocalypse, with John represented by an eagle. It is possibly also a reference to the height that John achieved when writing John 1.