“Go to Campo dei Fiori in Rome on 17 February and you will find yourself surrounded by a motley crowd of atheists, pantheists, anarchists, Masons, mystics, Christian reformers and members of the Italian Association of Free Thinkers … In the four centuries since he was executed for heresy by the Roman Inquisition, this diminutive iconoclast has been appropriated as a symbol by all manner of causes, reflecting the complexities and contradictions inherent in his ideas, his writings and his character.”