The Gospel's attribution to John Mark
It might first help for us to understand how the Gospel came to be named for John Mark.
John Mark is introduced at the end of Acts 12 as a companion of Paul and Barnabas (John Mark was apparently Barnabas' cousin; cf. Col 4.10), though earlier in the chapter his mother's home became a place of refuge for Peter. John Mark remained with Paul and Barnabas as they traveled. But John Mark eventually returned to Jerusalem before their planned trip was over, which soured his relationship with Paul. In Acts 15, John Mark was evidently still in Jerusalem, as was Peter.
By the late first century, a tradition had arisen that John Mark had become a close traveling companion of Peter (1 Pet 5.13). By the early second century, this tradition identified John Mark as the writer of Peter's memoirs.1 Around AD 110-120, Papias wrote:
Mark, the interpreter of Peter, wrote down carefully what he remembered, both the sayings and the deeds of the Christ, but not in chronological order, for he did not hear the Lord nor did he accompany him. At a later time, however, he did accompany Peter, who adapted his instructions to the needs, but not with the object of making a connected series of discourses of our Lord. So, Mark made no mistake in writing the individual discourses in the order in which he recalled them. His one concern was not to omit a single thing he had heard or to leave any untruth in this account.
This identification of John Mark as the author of Peter's recollection of Jesus is reiterated by Irenaeus in Against Heresies 3.1, in the now traditional order of the four canonical Gospels:
Matthew also issued a written Gospel among the Hebrews in their own dialect, while Peter and Paul were preaching at Rome, and laying the foundations of the Church. After their departure, Mark, the disciple and interpreter of Peter, did also hand down to us in writing what had been preached by Peter. Luke also, the companion of Paul, recorded in a book the Gospel preached by him. Afterwards, John, the disciple of the Lord, who also had leaned upon His breast, did himself publish a Gospel during his residence at Ephesus in Asia.
The point of contention raised by modern scholarship, however, is this: Irenaeus wrote this nearly seventy years after Papias, and what Papias wrote does not make clear that he's talking about the text we call 'the Gospel of Mark'. Rather, Papias' description of John Mark transcribing an unorganized collection of discourses does not well fit the Gospel of Mark as we have it, which is a narrative with deliberate shape.2 (Likewise, Irenaeus' claim that Mark was written after Matthew is rejected by the vast majority of scholarship (even among Christians), since Mark was a source for Matthew, and neither originated in Hebrew.)
Internally, the Gospel's author does not self-identify. Because the earliest certain identification of the book's author doesn't come until the second half of the second century, scholars determined that was too late to be historically reliable.
If not John Mark, then who?
The majority consensus of the identity of the author the Gospel of Mark is that we don't know the person or persons who wrote the book. Their identity is unknown and unknowable.
However, scholars do make an effort to pin down the approximate time and location of the book's origin. This can help us understand what kind of person the author was, if not their specific identity.
While the prophecy in Mark 13 likely goes back to authentic apocalyptic teaching from Jesus, the careful arrangement of these teachings into a single chiastic structure, and its accentuation of war in Judea is believed to reflect the authors' awareness of the (First) Jewish-Roman War of AD 66-73. The New Oxford Annotated Bible (ed. Michael D. Coogan) prefaces the Gospel of Mark with this:
Because of the vague references to the destruction of Jerusalem in Mark 13 (contrast Mt 22.7; Lk 19.32), the Gospel is thought to have been composed just prior to the widespread Jewish popular revolt that began in 66 CE and the Roman reconquest and destruction of Jerusalem and the Temple in 70 CE. The language of the Gospel is that of popular spoken Greek.
The narrative in Acts presents Christians as meeting in the synagogues up through the early 60s. Sometime after the war, however, Christians and Judaism began to separate; no longer was the Christian movement considered a sect within Judaism, but a religion apart from it. Mark 13's prophecy contains a warning that Jesus' followers will suffer punishment within the synagogue setting (13.9); this would be consistent with the period before 'Christianity' and 'Judaism' separated, again suggesting a time of authorship before the end of the war.
As to its location of origin, though, various places have been suggested. Rome is common for the traditional view, given Peter's association with the city.3 Eckhard Schnabel, Mark: An Introduction and Commentary, outlines the evidence for this view:
Frequent Latinisms in Mark's text can be taken as internal evidence for Rome as provenance of the Gospel (e.g. 2:4, 9-12 krabattos, 'mat'; Lat. grabatus; 2:23 hodon poiein, 'make their way; Lat. iter facere; 3:6, 15:1 symboulion didonai, 'form a plan, plot'; Lat. consilium capere/dederunt; 3:6, 6:27 spekoulat r, 'courier, executioner'; Lat. speculator). Since many of these Latinisms are found in Koine Greek and also in the Gospels of Matthew and Luke, they do not prove that Mark wrote his Gospel in Rome, but their frequency in Mark favours a Roman origin.
Another common suggestion is Syria. Camille Focant, The Gospel According to Mark: A Commentary, pushes back:
If the Roman origin of Mark seems the most likely, another hypothesis has often been defended lately: that of a Syrian origin (Kee, Community, 102-3; Myers, Binding, 41; Schenk, Markusevangelium, 45-48). Defended notably by Kümmel (Einleitung, 70), it has been taken up recently by an American exegetical group according to which Mark betrays an interest turned not toward an urban population, but rather toward a rural world of illiterate peasants born in villages or small towns, either from Upper Galilee or from the south of Syria (Rohrbaugh, "Social Location"). This thesis has been supported by Theissen (Lokalcolorit, 248-61). His arguments have been justly criticized by van Iersel (36-39). The thesis has been taken up by Marcus (30-37): for him, if Mark 13 has made allusion to the Neronian persecution we would have expected to find there the figure of a pagan king as this emperor, a sort of beast as in the book of Daniel or in Revelation. On the other hand, according to him, the formulation of Mark 13 is completely adapted for people near the events of the Jewish War.
To summarize the thought process of modern scholarship:
- The traditional attribution of John Mark as the author of this Gospel narrative rests on evidence that is scant and late. The earliest piece of evidence (Papias) describes a text that does not resemble the Gospel of Mark.
- All things being equal, critical scholarship cannot favor one religion's claims of the supernatural or miraculous over another religion's (e.g. as 'impartial' historians, they cannot accept Christian claims of authentic prophecy over Muslim claims of authentic prophecy). Hence, even if Jesus made authentic predictions concerning the fall of Jerusalem and its temple, the specific arrangement of that material in the Gospel of Mark suggests the author was aware of the Jewish-Roman War of AD 66-73.
- Despite that awareness, the lack of specificity suggests the author was writing contemporary to the war. This is reinforced by Mark 13's implication that Christians are still accepted within the synagogue, albeit with tension.
- Latin-based vocabulary and idioms may indicate the book was written in Rome,
while the author's concern with the Jewish-Roman War (and a total lack of concern for Nero's persecution of Christians in Rome) may instead place the author in or near the Levant.
Who wrote the Gospel of Mark? We don't know. But we think he wrote circa AD 66-70, either in Rome or in the Levant, with some concern for the Jewish-Roman War and the people caught up in it.
1 Contrast Hippolytus' list of the Seventy Disciples, which identifies the Gospel-author, the cousin of Barnabas, and the one named 'John Mark' as three completely different men. This would be plausible, since 'Mark' was a common Greco-Roman name at the time.
2 It introduces John as the herald of the Messiah. Jesus is introduced, then goes on to teach Torah, dispense wisdom, heal the sick, exorcise demons, and even raise the dead. These culminate at the halfway point of the book, the end of chapter 8, where Jesus is identified for the first time as 'the Messiah', which is immediately connected with the revelation that he must die at the hands of Jerusalem's elite. This revelation is then brought up twice more in the next chapters, followed by his arrival in Jerusalem. Jesus disrupts the temple activities, then predicts its destruction. This leads into the crucifixion narrative and the empty tomb. The Gospel of Mark has a carefully constructed 'plot', with recurring themes, and even a chiasmus in chapter 13.
3 cf. 1 Peter 5.13 again, where Peter and Mark are associated with 'Babylon', a cipher for Rome that originated after the Jewish-Roman War. See here for more information.