The conference on “Radical Religious Communities in Premodern Societies”, sponsored by the EXPRO project jointly with the Hussite Museum, was held on 20-22 October 2021 in Tábor. During the hybrid event, twelve on-site and five on-line papers were read by participants from Canada, Czech Republic, Finland, Hungary, Israel, Italy, Switzerland, United Kingdom and United States. While the conference, postponed due to the pandemic, came too late to celebrate the 600th anniversary of the foundation of the radical revolutionary commune in Tábor, the participants were able, along with Tábor municipal authorities, to commemorate the extermination of the most radical Taborite sects in October 1421.