At the beginning of the 16th century, Luther in Wittenberg and Zwingli in Zurich challenged the authority of the church. The Reformation was characterized by many new movements. In 1525, Konrad Grebel and Felix Manz founded the Anabaptist movement in Zurich and the first believers were baptised.

Anabaptists gathered secretly to study the Bible and called for the baptism of exclusively adult believers. Their faith was based on personal confession, renunciation of violence, and separation from the church and other authorities. As the beliefs of the Anabaptists challenged the authorities, they were often arrested, tortured, and execution.

The movement, which was rejected by Catholics and reformers alike, also found supporters in Constance. The Anabaptist Ludwig Hätzer was executed as early as 1529. In 1579, the council issued stern warnings to several men and women after rigorous interrogations.