Protestantism developed its sense of identity primarily in response to external threats and criticisms rather than as a result of shared beliefs. In one sense, the idea of "Protestantism" can be seen as the creation of its opponents rather than of its supporters.

Manz, formerly one of Zwingli's closest allies, held that there was no biblical warrant for infant baptism. Refusing to recant his views, he was tied up and drowned in the River Limmat.

From the outset, Protestantism rejected the critical medieval distinction between the 'sacred' and 'secular' orders. While this position can easily be interpreted as a claim for the desacralization of the sacred, it can equally well be understood as a claim for the sacralization of the secular. As early as 1520, Luther had laid the fundamental conceptual foundations for created sacred space within the secular. His doctrine of the 'priesthood of all believers' asserted that there is no genuine difference of status between the 'spiritual' and the 'temporal' order. All Christians are called to be priests - and can exercise that calling within the everyday world. The idea of 'calling' was fundamentally redefined: no longer was it about being called to serve God by leaving the world; it was now about serving God in the world.