The 16th century was a time of upheaval throughout western Europe, when a movement to reform the Roman Catholic church split western Christendom into two opposing camps, as Protestants rejected the authority of the Pope.

Although the movement was ostensibly a religious one, it reflected deep underlying tensions in the social structure. In Switzerland, as elsewhere, it was accompanied by riots and destruction. Supporters of the reform all over Europe smashed the "idolatrous" statues and pictures in churches, and threw monks and nuns out of their monasteries, in many cases never to return.

But discontent went beyond obvious manifestation of discontent with the church to attack the very structure of society. "Extremist" Protestant movements like the Anabaptists, which found their followers in the rural regions and which among other things called for an end to tithes and rents, were forcibly repressed by mainstream Protestant leaders.

Theological debate gave rise to a debate about tolerance; Geneva adopted an authoritarian stance, imprisoning, expelling or even burning those Protestants who disagreed with the official line, while Basel became a centre of intellectual freedom.