nce was made the
test of adherence to the Roman Church as well as to the general
confederation of Christendom. Irenaeus was not the author of this
proceeding. How far Rome acted with the cooeperation or under the
influence of the Church of Asia Minor is a matter that is still
obscure,[34] and will probably never be determined with certainty. What
the Roman community accomplished practically was theoretically
established by Irenaeus[35] and Tertullian. The former proclaimed the
baptismal confession, definitely interpreted and expressed in an
Antignostic form, to be the apostolic rule of truth (regula veritatis),
and tried to prove it so. He based his demonstration on the theory that
this series of doctrines embodied the faith of the churches founded by
the Apostles, and that these communities had always preserved the
apostolic teaching unchanged (see under C).

Viewed historically, this thesis, which preserved Christianity from
complete dissolution, is based on two unproved assumptions and on a
confusion of ideas. It is not demonstrated that any creed emanated from
the Apostles, nor that the Churches they founded always preserved their
teaching in its original form; the creed itself, moreover, is confused
with its interpretation. Finally, the existence of a _fides catholica_,
in the strict sense of the word, cannot be justly inferred from the
essential agreement found in the doctrine of a series of
communities.[36] But, on the other hand, the course taken by Irenaeus was
the only one capable of saving what yet remained of primitive
Christianity, and that is its historical justification. A _fides
apostolica_ had to be set up and declared identical with the already
existing _fides catholica_. It had to be made the standard for judging
all particular doctrinal opinions, that it might be determined whether
they were admissible or not.

The persuasive power with which Irenaeus set up the principle of the
apostolic "rule of truth," or of "tradition" or simply of "faith," was
undoubtedly, as far as he himself was concerned, based on the facts that
he had already a rigidly formulated creed before him and that he had no
doubt as to its interpretation.[37] The rule of truth (also [Greek: he
hypo tes ekklesias keryssomene aletheia] "the truth proclaimed by the
Church;" and [Greek: to tes aletheias somation], "the body of the
truth") is the old baptismal confession well known to the communities
for which he immediately writes. (Se