Atheism is a powerful presence in modern society and discourse, but its position has been radically different in past stages of history. This panel treats the many different pre-modern forms of unbelief, from classical skepticism, to medieval fictional dialogs between theologians and mock atheists, to Renaissance and Reformation attempts to diagnose atheism as a form of mental illness, to atheism's crosspolination with deism and other radical movements in the Enlightenment. How can atheism's many past forms and transformations inform worldbuilding, especially in fiction in which theology or divine forces play an active role?