Poland and Ireland are alone, or nearly so, the only countries which have remained loyal, because, with these, the Catholic faith, under the long pressure of public calamities, has become incorporated with national sentiment.
Elsewhere the Roman deposit is non-existent or too thin.

On the contrary, all the populations that were once Latinized have at bottom remained Catholic; four centuries of imperial rule and of Roman assimilation have deposited in them of layers of habits, ideas and sentiments which endure.[5329] To measure the influence of this historic layer it is sufficient to note that three elements compose it, all three contemporary, of the same origin and of the same thickness, a Roman language, the civil law of Rome, and Roman Christianity; each of these elements, through its consistence, indicates the consistence of the others.
Hence the profound and established characteristics by which the Catholic branch now distinguishes itself from the other two issuing from the same Christian trunk.

With the Protestants, the Bible, which is the Word of God, is the sole spiritual authority; all the others, the Doctors, Fathers, tradition, Popes and Councils, are human and, accordingly, fallible; in fact, these have repeatedly and gravely erred.[5330] The Bible, however, is a text which each reader reads with his own eyes, more or less enlightened and sensitive, with eyes which, in Luther's time, possessed the light and sensibility of the sixteenth century, and which, at the present time, read with the sensibility and light of the nineteenth century; so that, according to epochs and groups, the interpretation may vary, while authority, if not as regards the text, or at least its meaning, belongs wholly to the individual.

With the Greeks and Slavs, as with the Catholics, it belongs only to the Church, that is to say to the heads of the Church, the successors of the apostles.
But with the Greeks and Slavs, since the ninth century, the Church had decreed no new dogmas; according to her, revelation had stopped; the creed was finished, final and complete, and there was nothing to do but to maintain it .-- On the contrary, with the Catholics, after as before that date, the creed never ceased developing itself, always becoming more precise, and revelation kept on; the last thirteen councils were inspired like the first seven, while the first one, in which Saint Peter at Jerusalem figured, enjoyed no more prerogatives than the last one convoked by Pius IX.

at the Vatican.