nt everywhere--except in outlying communities. Catholicism,
essentially as we conceive it now, was what most of the Churches had
arrived at. Now it is an _a priori_ probability that this transformation
of Christianity, which was simply the adaptation of the Gospel to the
then existing Empire, came about under the guidance of the metropolitan
Church,[301] the Church of Rome; and that "Roman" and "Catholic" had
therefore a special relation from the beginning. It might _a limine_ be
objected to this proposition that there is no direct testimony in
support of it, and that, apart from this consideration, it is also
improbable, in so far as, in view of the then existing condition of
society, Catholicism appears as the _natural and only possible_ form in
which Christianity could be adapted to the world. But this is not the
case; for in the first place very strong proofs can be adduced, and
besides, as is shown by the development in the second century, very
different kinds of secularisation were possible. In fact, if all
appearances are not deceptive, the Alexandrian Church, for example, was
up to the time of Septimius Severus pursuing a path of development
which, left to itself, would _not_ have led to Catholicism, but, in the
most favourable circumstances, to a parallel form.[302]

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 th