But why?
Firstly: the problem wasn’t to know if God existed, but how to believe in God. Secondly: the Christian “family” includes church-going Catholics, temple-going Protestants and Orthodox Christians.
And the Bible?
It’s what they all have in common. But until 1962, the Catholic Bible and Mass were in Latin, while the Reformed (Protestants) have always used French.
Still, it’s simpler ….
Everything’s simpler in Protestantism: no saint, no bishop, you access God directly by reading the Bible, whereas for Catholics, you do it through the priest.
And the “Vaudois”?
Valdésius founded the “Pauvres de Lyon” in 1170, translating the Bible into Franco-Provençal. They were condemned for preaching without being priests, and called Vaudois by the judges of the Inquisition. They fled to Italy. From Piedmont, the Vaudois faith spread more to Freissinières in the Ecrins, for example, than to the Queyras. In 1532, the Vaudois joined Protestantism. Italian Protestants, on the other hand, are still called Vaudois!
And the religious wars?
They began in 1562, with the distruction of Queyras churches and the construction of temples. The Edict of Nantes restored peace in 1598, organizing cohabitation between the two faiths. Churches were rebuilt in the 17th century. In 1685, Louis XIV revoked the Edict of Nantes. In every Protestant family, one brother abjured to remain in the Queyras, the other went into exile to remain faithful to his convictions.