His uncle of Bavaria, in letters to his son and nephew, had stamped into their minds with the enthusiasm of perfect conviction that all happiness and blessing for governments depended on the restoration and maintenance of the unity of the Catholic faith.

All the evils in times past and present resulting from religious differences had been held up to the two youths by the Jesuits in the most glaring colours.

The first duty of a prince, they had inculcated, was to extirpate all false religions, to give the opponents of the true church no quarter, and to think no sacrifice too great by which the salvation of human society, brought almost to perdition by the new doctrines, could be effected.
Never had Jesuits an apter scholar than Ferdinand.

After leaving school, he made a pilgrimage to Loretto to make his vows to the Virgin Mary of extirpation of heresy, and went to Rome to obtain the blessing of Pope Clement VIII.
Then, returning to the government of his inheritance, he seized that terrible two-edged weapon of which the Protestants of Germany had taught him the use.
"Cujus regio ejus religio;" to the prince the choice of religion, to the subject conformity with the prince, as if that formula of shallow and selfish princelings, that insult to the dignity of mankind, were the grand result of a movement which was to go on centuries after they had all been forgotten in their tombs.

For the time however it was a valid and mischievous maxim.