He appears in fragments from the church father Papias of Hierapolis as one of the author's sources and is first unequivocally distinguished from the Apostle by Eusebius of Caesarea.
John the Presbyter appears in a fragment by Papias, an early 2nd-century bishop of Hierapolis, who published an "Exposition of the Sayings of the Lord" (Greek κυριακῶν λογίων ἐξηγήσις — Kyriakôn logiôn exêgêsis) in five volumes.
In modern times, the distinction was frequently revived, mainly – and quite in contrast to Eusebius' views – "to support the denial of the Apostolic origin of the Fourth Gospel",[5] whose "beauty and richness" some scholars had difficulty in ascribing to a "fisherman from Gallilee".
[6] Much of traditional Church scholarship squarely attributed all the Johannine books of the New Testament to a single author, the Apostle John.
[5] To support this view, it related four main arguments: In his "Letter to Florinus", which survives as a fragment, Irenaeus speaks of "Polycarp having thus received [information] from the eye-witnesses of the Word of life" including John, and as a "blessed and apostolical presbyter".