A major Arts and Humanities Research Council funded project, situated in the Department of History, University of York, and running for five years, from May 2014 until April 2019. The research team consists of Professor Peter Biller, Dr Lucy Sackville, and Dr Shelagh Sneddon. The project focuses on four mainly unedited inquisition registers that were produced during the earliest years of inquisition in Languedoc, 1235-44. The project is producing an edition and English translation of these, together with technical apparatus. These materials provide the foundation for research which will transform our understanding of inquisition into heresy in the crucial first decade of its development.