Dating the books of the Bible is not an exact science. Even Biblical critics point to wide ranges of possible dates. The method de jour of dating the various books is to line them up with perceived theological or cultural developments. Of course, biases force interpretations on these evidences. For example, although Matthew is heavily Jewish and the earliest missions were exclusively to the Jews, Mark is dated by liberals as before Matthew because it is shorter.

The evidence, however, points to Matthew as the earliest gospel. Both tradition and the fact that the issues dealt with in Matthew are thoroughly Jewish points to an early date for Matthew.

Mark is more abridged. It does retain the Hebrew concerns about Genealogy, but it specifically cuts other Hebrew concerns from the text. This is what would be expected if tradition is correct. Tradition places Mark as written based on the teachings of Peter while Peter was in Rome. Notice that Rome had a thoroughly metropolitan Jewish population, even gaining converts from the Gentiles. This fact is even noted by Cassius Dio (c. 150 – 235AD):

the country has been named Judaea, and the people themselves Jews. I do not know how this title came to be given to them, but it applies also to all the rest of mankind, although of alien race, who affect their customs. This class exists even among the Romans, and though often repressed has increased to a very great extent and has won its way to the right of freedom in its observances.

The vast Jewish population in Rome, along with their Gentile converts, and traditions as to the mission of Peter and Mark makes a very compelling case for why Mark was written in the manner it was. It would fit very nicely into the timeframe before the Jews were expelled from Rome (49AD). Interestingly, they were expelled for “rioting at the instigation of Chrestus.”

So when was the church of Rome founded and by whom? Some, such as John AT Robinson, point to Act 12 as a possible date at which Peter would travel to Rome and found the church. He states a probable date for this is 42AD because “There is ground therefore for thinking that Edmundson may be right in dating the death of James and the imprisonment of Peter in the spring of 42 as part of Herod’s attempt to ingratiate himself with the Jews (cf. Josephus, Ant. 19.2931.)”

As seen in the passage, Peter is imprisoned, escapes, and flees (presumably outside the authority of Herod):

Act 12:1 Now about that time Herod the king stretched forth his hands to vex certain of the church.
…
Act 12:5 Peter therefore was kept in prison…

He escapes and goes to stay with Mark:

Act 12:11 And when Peter was come to himself, he said, Now I know of a surety, that the Lord hath sent his angel, and hath delivered me out of the hand of Herod, and from all the expectation of the people of the Jews.
Act 12:12 And when he had considered the thing, he came to the house of Mary the mother of John, whose surname was Mark; where many were gathered together praying.
…
Act 12:17 But he, beckoning unto them with the hand to hold their peace, declared unto them how the Lord had brought him out of the prison. And he said, Go shew these things unto James, and to the brethren. And he departed, and went into another place.

This “another place” might be Rome. A thorough search was performed for Peter within Herod’s purview, but Peter was not found. This does re-enforce the case that Peter left for Rome, probably bringing with him Mark, and there founded the church. Herod’s search is detailed in the proceeding verses:

Act 12:18 Now as soon as it was day, there was no small stir among the soldiers, what was become of Peter.
Act 12:19 And when Herod had sought for him, and found him not, he examined the keepers, and commanded that they should be put to death. And he went down from Judaea to Caesarea, and there abode.

The “he” is talking of Herod, giving up and retiring to Caesarea (the seat of the Roman procurators). Peter was long gone and does not show up again until the Jerusalem council occurred (circa 47AD). Rome is a highly probable place to where he waited. We know it was an early established church established by someone other than Paul (alluded to in Rom 15:20) so must have been established well before Romans was written (circa 60AD). Peter is the prime suspect, which places him in Rome between 42 and 47 AD (at least though 44AD when Herod dies).

Traditions claim Mark was written after Peter left Rome, as recorded by Eusebius:

And thus when the divine word had made its home among them [the Christians in Rome]… And so greatly did the splendor of piety illumine the minds of PETER’S hearers that they were not satisfied with hearing once only, and were not content with the unwritten teaching of the divine Gospel, but with all sorts of entreaties they besought MARK, a follower of Peter, and the one whose Gospel is extant, that he would leave them a written monument of the doctrine which had been orally communicated to them. Nor did they cease until they had prevailed with the man, and had thus become the occasion of the written Gospel which bears the name of MARK… Clement in the eighth book of his Hypotyposes gives this account, and with him agrees the bishop of Hierapolis named Papias.

With all these in mind, Mark can conceivably be dated to 45AD. In the words of John AT Robinson:

One must therefore, I believe, be prepared to take seriously the tradition that Mark, at whose home in Jerusalem Peter sought refuge before making his hurried escape (Acts 12.12-17) and whom later in Rome he was to refer to with affection as his ‘son’ (I Peter 5.13), accompanied Peter to Rome in 42 as his interpreter and catechist, and that after Peter’s departure from the capital he acceded to the reiterated request for a record of the apostle’s preaching, perhaps about 45. Mark himself was certainly back in Jerusalem by the end of the famine visit, in 46 or 47 (Acts 12.25). We have no record of his being in Rome again till the mid-6os (to anticipate the date and place of I Peter).