My doctoral research explores the state of religion in post-reformation Protestant lands around 1700 through the case of a supraconfessional correspondence network of pious visionaries, led by Johanna Eleonora Petersen (1644-1724) and others. As intellectual and religious thought of the period has mostly been researched either in light of the Enlightenment or in the field of church history, my dissertation focuses on strands of religious thought and life that do not fit neatly into these historiographical trajectories. It examines the extensive network of Johanna Eleonora Petersen and seeks to understand its interests and the way it functioned. Although these individuals were dismissed by both orthodox theologians and early Enlightenment thinkers as “enthusiasts”, they had also attracted a group of followers, including duchesses and princesses. My research will try to illustrate the blurry status of these “enthusiasts” and raise questions about the complexity of religious life against what is thought to be the beginning of secularisation.