1. The Shepherd of Hermas
The Shepherd of Hermas is an early second century church document. We’re interested particularly in Visions 2.4 and 3.9, which indicate a plurality of eldership in Rome as opposed to a monarchical episcopate:
But you yourself will read it to this city [Rome], along with the elders (presbuteroi) who preside (proistamenoi – plural leadership) over the church. (Vis 2.4)
Now, therefore, I say to you [plural] who lead the church and occupy the seats of honor: do not be like the sorcerers. For the sorcerers carry their drugs in bottles, but you carry your drug and poison in your heart. You are calloused and do not want to cleanse your hearts and to mix your wisdom together in a clean heart, in order that you may have mercy from the great King. Watch out, therefore, children, lest these divisions of yours [among you elders] deprive you of your life. How is it that you desire to instruct God’s elect, while you yourselves have no instruction? Instruct one another, therefore, and have peace among yourselves, in order that I too may stand joyfully before the Father and give an account on behalf of all of you to your Lord. (Vis 3.9)
If there is anywhere we should expect petrine succession mentioned, this would be a prime candidate, because a petrine office would have been the ideal solution to bishops fighting among themselves about who was greatest! But Hermas talks about multiple people who “lead the church”, and makes no mention of such an office. The most reasonable conclusion, therefore, is that leadership was indeed divided among a number of elders, and no such monarchical office existed.
2. House churches in Rome
There seem to only have been house churches in Rome in the first–early second centuries. This is the likely reason 1 Clement repeatedly emphasizes hospitality along with faith (1.2; 10.7; 11.1; 12.1-3)—because of the natural conflict between house patrons and church elders. Paul also indicates a knowledge of as many as six house churches in Rome, one of which was associated with the Jewish Christian leaders Aquila and Priscilla (Rom 16:3-15). In a strikingly odd turn of events for Catholics, he forgets to mention Peter in Romans 16! William L Lane draws together multiple lines of evidence pointing to house churches, in “Social Perspectives on Roman Christianity during the Formative Years from Nero to Nerva: Romans, Hebrews, 1 Clement”, a paper he contributed to Judaism and Christianity in First-Century Rome, ed Karl P. Donfried and Peter Richardson (Grand Rapids, MI, Cambridge, UK: William B. Eerdmans Publishing Company, 1998). His conclusion:
Christians in Rome during this formative period appear to have met as ‘household’ groups in privately owned locations scattered around the capital city. They constituted a loose network of house churches, without any central facility for worship. The absence of central coordination matches the profile of the separated synagogues in Rome during this period.
In other words, not only was there no monepiscopate during this time, but there was no central episcopate at all.
3. Peter and Paul did not found the church in Rome
There is utterly no contemporary evidence that Peter or Paul founded the church of Rome; rather, it is likely that the Roman Jews among the 3,000 converted in Acts 2 took their faith back to their city and started churches there. It isn’t until much later that we get the claim of Peter and Paul founding the church of Rome; a claim hard to reconcile with Paul’s extremely diplomatic, almost apologetic tone when writing to that church, as compared to his tone when addressing churches he actually had founded, such as you’ll find in 1 and 2 Corinthians. And it’s not until Eusebius, over 300 years later, that we start getting claims about Peter residing in Rome (and as you probably know, Eusebius was not exactly a reliable historian). How would he know, in 354 AD, what Peter was up to in the first century? We can safely conclude that Eusebius is just engaging in some legendary embellishment, since Paul, in Galatians 2:7-9, knows that Peter is still in Jerusalem in 49 AD for the council!
As Eamon Duffy put it on page 2 of Saints and Sinners: A History of the Popes:
These stories were to be accepted as sober history by some of the greatest minds of the early Church—Origen, Ambrose, Augustine. But they are pious romance, not history, and the fact is that we have no reliable accounts either of Peter’s later life or the manner or place of his death. Neither Peter nor Paul founded the Church at Rome, for there were Christians in the city before either of the Apostles set foot there. Nor can we assume, as Irenaeus did, that the Apostles established there a succession of bishops to carry on their work in the city, for all the indications are that there was no single bishop at Rome for almost a century after the deaths of the Apostles. In fact, wherever we turn, the solid outlines of the Petrine succession at Rome seem to blur and dissolve.
4. The existence of the book of Romans
Why did Paul need to write the epistle to the Romans if they had the benefit of Peter’s direct oversight and teaching? After all, this was smack in the middle of the period traditionally ascribed to Peter’s “reign”. Paul wrote in about 56 AD; Peter was supposed to have been pope from 32–67 AD (or pick your tradition) before Linus took over. Yet apparently the church of Rome not only needed serious theological training (Romans is the most systematically theological of all the epistles), but also suffered from in-fighting (ch 14-15).
Forgeries and fabrications
Finally, we know that much of the “evidence” used by the developing Catholic Church to bolster its historical claims about the papacy are simply forgeries or fabrications. It would get tedious to keep quoting historians, but John Bugay has put together a good summary titled The Fictional Beginnings of Papal Infallibility.
All of this together builds an extremely strong cumulative case against any kind of monarchical episcopate in Rome until at least the middle of the second century. Indeed, John Reuman observes,
Biblical and patristic studies make clear that historically a gap occurs at the point where it has been claimed “the apostles were careful to appoint successors in” what is called “this hierarchically constituted society,” specifically “those who were made bishops by the apostles…,” an episcopate with an “unbroken succession going back to the beginning.” For that, evidence is lacking, quite apart from the problem that the monepiscopacy replaced presbyterial governance in Rome only in the mid-or late second century. It has been noted above how recent treatments conclude that in the New Testament no successor for Peter is indicated.”
And Herman Pottmeyer notes that “the historical facts are not disputed”. This overall picture simply lacks anything resembling a papacy. Moreover, it includes features that are antithetical to such a thing. So the burden of proof rests heavily on the Catholic to establish the historical claim that Peter was primate of Rome and was succeeded by a continuing office. Yet there seems no possible way for them to shoulder that burden. Even going as far back as 1927, Shotwell and Loomis recognized that,
For example, the first definite statement which has come down to us that Peter and Paul founded the Roman church, is made by Dionysius of Corinth about 170 A.D. That is a long way from contemporary evidence. We have no lists of the early bishops of Rome until about the same period, and those we have do not quite agree. There is almost a blank, as far as precise documentary evidence goes, for the preceding century; and that was a century of turmoil, persecution and obscurity for the Christians, in which mythical legends of saints and martyrs were springing up. The Christians themselves were, according to pagan critics, rather credulous people and were living under that high emotional pressure in which historic accuracy is of relatively little importance compared with the free life of the spirit. The great growth of what we call spurious apostolic literature in this and the following period points to a continuance of the same unscientific and unhistorical habits of mind. Who, under such circumstances, would be prepared to accept a text a century old as adequate evidence for any historical fact? James T. Shotwell, Louise Ropes Loomis, “The See of Peter,” “Records of Western Civilization” series, New York: Columbia University Press, 1927, 1955, 1991, pp xix-xxii