Violence perpetrated in the name of religious or moral regeneration is neither new nor peculiar to any particular creed or ideology. It is an ancient phenomenon, the history and psychology of which have been extensively studied, especially in Northern and Central Europe.

The paper considers a case history of one major manifestation of it in the twentieth century, and related attempts to conceptualize key problems it raises. A link is made with the more recent research of James Gilligan, a leading modern theorist of violence. This wider perspective is needed if we are to understand and combat the re-emergence of the phenomenon today.