Thomas Kirchner studies Aachen as a municipality with adherents of three Christian denominations which created the prerequisites for a peaceful coexistence temporarily between 1555 and 1618. The story of the religious crises in Aachen took place at time of conflicts between denominations in which hostilities between Protestants and Catholics destabilized Aachen between 1560 and 1614 before the Catholics finally prevailed. Kirchner analyzes the surprisingly peaceful converse side of the Aachen municipality whose members were Catholics, Lutherans and members of the Reformed Church. It was on the political stage, but also in guilds of craftsmen and churches as well as in everyday city life, that alternative actions to denominational fundamentalism took shape. The results of the study show how denominational coexistence in cities can be understood during the "confessional age."