Outsidethecamp is just saying nothing is recorded in the NT of Peter going to Rome. The book of Acts is the NT record of the Early Church.
And that record isn't the entire story of the early Church. That record is the part of the story that the Church has received as holy and canonical Scripture.
History didn't stop when St. Paul was imprisoned in Rome.
Since Scripture doesn't record what happened to Peter, or Paul, or Thomas then it's not a bad idea to see, at the very least, what Christians seemed to have understood to have happened to them. And, as it turns out, in some cases the record of what happened to the Apostles exists in the writings of those Christians who lived in the generations after the Acts was written; in some cases there are conflicting legends, but in other cases the testimony of the ancient Christian Church sheds some pretty clear light on the subject.
Clement wrote near the end of the 1st century, and speaks of both Paul and Peter as martyrs who gave their lives to the cause of Christ, Clement is speaking as a Christian leader in Rome and speaks of their deaths as being part of the living memory of the Church in Rome. Other Christians in the years to come spoke, likewise, of both Paul and Peter as having suffered martyrdom in Rome, during the reign of Nero. Paul having been beheaded, and Peter receiving death by crucifixion--a fate which some of the other Apostles, such as Peter's brother Andrew, likewise suffered. Seeing as we know, historically, that Nero chose to blame Christians for the great fire that broke out in Rome and took to task to murdering Christians en masse. For example lighting up his imperial gardens by covering Christians in pitch, hanging them on stakes and setting them on fire.
The idea that Paul and Peter were among the victims of this major persecution of the Church is hardly a fanciful idea.
That Peter was in Rome is attested to by many in the ancient Church; which does not credence to the Roman Catholic teaching on the papacy. And that's kind of a big point to make here because, quite frankly, I'm convinced the big reason for the argument here that Peter wasn't in Rome isn't really about evaluating history, it's about coming up with reasons to reject the Roman Catholic teaching on the papacy.
That Peter was in Rome, martyred in Rome, and was bishop of Rome is a well-attested fact of Christian history and tradition--one that is shared by millions of non-Roman Catholic Christians who have always recognized this fact but have never accepted the peculiar Roman Catholic belief in the papacy. Peter's episcopacy in Rome does not establish the papacy, it merely establishes Peter's episcopacy in Rome. It is entirely possible to recognize that the pope sits in St. Peter's chair while also recognizing that the institution of the papacy is a radical departure and innovation of the Western medieval Church that does not represent the reality of the ancient Church or the views held by millions of Christians in the East for the last two millennia.
Exegesis, theology, and historical inquiry must be objective, not based upon an ideological prejudice.
-CryptoLutheran