There is a case to be made that John, the son of Zebedee, had already died long before the Gospel of John came to be written.
It is worth noting for its own sake, even though the "beloved disciple" need not be identified with John, the son of Zebedee.
In his ninth century Chronicle in the codex Coislinianus, George Hartolos says, "[John] was worth of martyrdom." Hamartolos proceeds to quote Papias to the effect that, "he [John] was killed by the Jews." In the de Boor fragment of an epitome of the fifth century Chronicle of Philip of Side, the author quotes Papias: Papias in the second book says that John the divine and James his brother were killed by Jews. 369-370): "That Papias source of information is simply an inference from Mark -40 or its parallel, Matt. None the less, this Marcan passage itself affords solid ground.
No reasonable interpretation of these words can deny the high probability that by the time these words were written [ca.
70 CE] both brothers had 'drunk the cup' that Jesus had drunk and had been 'baptized with the baptism' with which he had been baptized." Since the patristic tradition is unanimous in identifying the beloved disciple with John, at least this evidence discredits the patristic tradition concerning the authorship of the Gospel of John.