The Ebionite document, called "The Preaching of Peter," produced about the time of Ignatius, or very soon after, and used by Heracleon in Hadrian's time, is manifestly founded on the undisputed fact of S. Peter having labored at Rome. It is inconceivable that the author of the Ebionite document should have put forward a groundless fable, about the theatre of S. Peter's operations, at a time when many who had seen him must have been still alive. Eusebius, who had the writings of Papias (and Hegesippos) before him, maintains with Clement, that S. Peter wrote his Epistle at Rome (Euseb. ii. 15). Papias, a disciple of S. John, speaking of this epistle declares that "Babylon" means expressly the capital of the empire. Hegesippos, a Christian Jew of Palestine, who came to Rome in the first half of the second century, makes Linus the first bishop after the apostles, in accordance with Irenæus, who says: "After Peter and Paul had founded the Roman church and set it in order, they gave over the episcopate to Linus." If we consider that Hegesippos came to Rome to investigate, among other things, the succession of local bishops for the short period of eighty-three years, that he certainly spoke with persons whose fathers could remember the presence of the apostles, we cannot help accepting his evidence as conclusive.
The main objection brought forward by the opponents is that, after the incident at Antioch, we have no positive knowledge of the actions and travels of S. Peter. Still, there is nothing to contradict the assumption of his journey to Rome, and his confession and execution there. The fact was so generally known that nobody took the trouble to write a precise statement of it, because nobody dreamed that it could be denied. How is it possible to imagine that the primitive Church did not know the place of the death of its two leading apostles? In default of written testimony let us consult monumental evidence.
There is no event of the imperial age and of imperial Rome which is attested by so many noble structures, all of which point to the same conclusion,--the presence and execution of the apostles in the capital of the empire. When Constantine raised the monumental basilicas over their tombs on the Via Cornelia and the Via Ostiensis; when Eudoxia built the church ad Vincula; when Damasus put a memorial tablet in the Platonia ad Catacumbas; when the houses of Pudens and Aquila and Prisca were turned into oratories; when the name of Nymphæ Sancti Petri was given to the springs in the catacombs of the Via Nomentana; when the twenty-ninth day of June was accepted as the anniversary of S. Peter's execution; when Christians and pagans alike named their children Peter and Paul; when sculptors, painters, medallists, goldsmiths, workers in glass and enamel, and engravers of precious stones, all began to reproduce in Rome the likenesses of the apostles, at the beginning of the second century, and continued to do so till the fall of the empire; must we consider them all as laboring under a delusion, or as conspiring in the commission of a gigantic fraud? Why were such proceedings accepted without protest from whatever city, from whatever community, if there were any other which claimed to own the genuine tombs of SS. Peter and Paul? These arguments gain more value from the fact that the evidence on the opposite side is purely negative. It is one thing to write of these controversies at a distance from the scene of the events, in the seclusion of one's own library; but quite another to study them on the spot, and to follow the events where they took place. If my readers had the opportunity of witnessing the discoveries made lately in the Cemeterium Ostrianum, and the Platonia ad Catacumbas; or of examining Grimaldi's manuscripts and drawings relating to the old basilica of Constantine; or Carrara's account of the discoveries made in 1776 in the house of Aquila and Prisca, they would surely banish from their minds the last shade of doubt.