France, Dec. 13 -- Under the monarchy, the Catholic Church held major privileges and played a central role in society. The French Revolution of 1789 upended this order. Revolutionaries nationalised church property and required priests to swear allegiance to the new republic. Those who refused were persecuted.

Napoleon later tried to ease tensions by signing the Concordat of 1801 with Pope Pius VII. The state recognised Catholicism as the faith of most French people, but also recognised Reformed Protestant, Lutheran and Jewish communities. It appointed bishops and paid the clergy.

This system lasted throughout the 1800s but kept tensions high - particularly under the Third Republic, when republicans viewed the church as blocking modern r...