We have historical information from Josephus (a reputable source) stipulating that Herod Agrippa died in A.D.45. As pointed out in post # 1438 Peter was in and about Jerusalem from Pentecost to A.D. 54. We know for a fact he was there at the Council in A.D. 51. I never said Peter was delivered from prison the same year Herod died.....but obviously Herod died thereafter....and we know when it was (45 A.D.).
It is likely that Paul knew that Peter was traveling away from Rome at that time. Given Peter's authority, only upon Peter's absence would Paul have written such an apostolic letter.
Why would this be likely? Paul was given the authority, not Peter. To presuppose that Peter was anywhere in or about Rome at any time is speculation.
There are other alternatives to which you are not giving sufficient consideration. One is that Mark the nephew of Barnabas is not the "John Mark" of Acts 12 who wrote the Gospel of Mark and became the first bishop of Alexandria.
The reason we know that this Mark is the companion of Peter is that Paul is asking for Timothy to also stop and get his "scrolls and parchments" at Troas. He had evidently left them there when he had been arrested the final time and wanted to make sure these "Scriptures" [2 Peter 3:15-16] would be placed in safe hands....probably having Mark and Timothy take them to the Apostle John. Mark, of course, would be bringing along with him all of Peter's writings as well as the Book of Mark. Paul was already in possession of the works of Luke....as Luke was with him. Jude and the Book of Hebrews, I'm certain, would also have been among Paul's possessions at that time.
I believe you see the initial canonizing of the New Testament here. Certainly by that time the Book of Matthew had been copied countless times and as soon as John received the "Parchments, Scrolls, Peter's writings and Luke's" he would have added his own books and we would then have had all of New testament scripture present for the early churches. We do know that John and the Greeks safe guarded the original writings.
There is no Biblical record of Peter ever having been in or about Rome and much evidence points to the contrary. It makes no sense that scripture would be completely silent about his presence there if he was that instrumental in the development of the Roman Church.
#1450 Bump