In 1553, physician and theologian Michael Servetus was burned for heresy in Geneva after rejecting orthodox Trinitarian doctrine. The case involved Protestant as well as Catholic intolerance. It became a major controversy over conscience, religious authority, and punishment.

Servetus's death influenced later writing about toleration and freedom of thought. It helped create a literary and philosophical tradition in which the solitary thinker faces institutional cruelty, a theme important to Enlightenment prose and dissenting poetry.