A major Arts and Humanities Research Council funded project, situated in the Department of History, University of York, that ran for five years, from May 2014 until April 2019. The research team consisted of Professor Peter Biller, Dr Lucy Sackville, and Dr Shelagh Sneddon. The project was focused on four mainly unedited inquisition registers that were produced during the earliest years of inquisition in Languedoc, 1235-44. The research team is now producing an edition and English translation of these, together with technical apparatus, that will be published by Brill. These materials will provide the foundation for research that will transform our understanding of inquisition into heresy in the crucial first decade of its development. Alongside the edition, this website will continue to present news and materials of interest to the scholar of medieval inquisition.