which, while the Church was still one, was divided between two dioceses,
Italy and Dacia, and when the Church itself was divided, in the eleventh
century, was torn apart between the two beliefs. The dividing line between
the jurisdictions of Rome and Constantinople ran from north to south
through Bosnia, but naturally there has always been a certain vagueness
about the extent of their respective jurisdictions. In later years the
terms Croat and Roman Catholic on the one hand, and Serb and Orthodox on
the other, became interchangeable. Hercegovina and eastern Bosnia have
always been predominantly Orthodox, Dalmatia and western Bosnia
predominantly Roman Catholic. The loyalty of the Croatians to
Austria-Hungary has been largely owing to the influence of Roman
Catholicism.

During the first centuries of Serbian history Christianity made slow
progress in the western half of the Balkan peninsula. The Dalmatian coast
was always under the influence of Rome, but the interior was long pagan.
It is doubtful whether the brothers Cyril and Methodius (cf. chap. 5)
actually passed through Serb territory, but in the tenth century their
teachings and writings were certainly current there. At the time of the
division of the Churches all the Serb lands except the Dalmatian coast,
Croatia, and western Bosnia, were faithful to Constantinople, and the
Greek hierarchy obtained complete control of the ecclesiastical
administration. The elaborate organisation and opulent character of the
Eastern Church was, however, especially in the hands of the Greeks, not
congenial to the Serbs, and during the eleventh and twelfth centuries the
Bogomil heresy (cf. chap, 6), a much more primitive and democratic form of
Christianity, already familiar in the East as the Manichaean heresy, took
hold of the Serbs' imagination and made as rapid and disquieting progress
in their country as it had already done in the neighbouring Bulgaria;
inasmuch as the Greek hierarchy considered this teaching to be