It can, however, be proved that it was in the Roman Church, which up to about the year 190 was closely connected with that of Asia Minor, that all the elements on which Catholicism is based first assumed a definite form.[303] (1) We know that the Roman Church possessed a precisely formulated baptismal confession, and that as early as the year 180 she declared this to be the apostolic rule by which everything is to be measured. It is only in her case that we are really certain of this, for we can merely guess at it as regards the Church of Smyrna, that is, of Asia Minor. It was accordingly admitted that the Roman Church was able to distinguish true from false with special exactness;[304] and Irenaeus and Tertullian appealed to her to decide the practice in Gaul and Africa. This practice, in its precisely developed form, cannot be shown to have existed in Alexandria till a later period; but Origen, who testifies to it, also bears witness to the special reverence for and connection with the Roman Church. (2) The New Testament canon, with its claim to be accounted catholic and apostolic and to possess exclusive authority is first traceable in her; in the other communities it can only be proved to exist at a later period. In the great Antiochian diocese there was, for instance, a Church some of whose members wished the Gospel of Peter read; in the Pentapolis group of congregations the Gospel of the Egyptians was still used in the 3rd century; Syrian Churches of the same epoch used Tatian's Diatessaron; and the original of the first six books of the Apostolic Constitutions still makes no mention of a New Testament canon. Though Clement of Alexandria no doubt testifies that, in consequence of the common history of Christianity, the group of Scriptures read in the Roman congregations was also the same as that employed in public worship at Alexandria, he had as yet no New Testament canon before him in the sense of Irenaeus and Tertullian. It was not till Origen's time that Alexandria reached the stage already attained in Rome about forty years earlier. It must, however, be pointed out that a series of New Testament books, in the form now found in the canon and universally recognised, show marks of revision that can be traced back to the Roman Church.[305] Finally, the later investigations, which show that after the third century the Western readings, that is, the Roman text, of the New Testament were adopted in the Oriental MSS. of the Bible,[306] are of the utmost value here; for the most natural explanation of these facts is that the Eastern Churches then received their New Testament from Rome and used it to correct their copies of books read in public worship.[307] (3) Rome is the first place which we can prove to have constructed a list of bishops reaching back to the Apostles (see Irenaeus).[308] We know that in the time of Heliogabalus such lists also existed in other communities; but it cannot be proved