(1866-1953) defined Medieval Inquisition as "... a system of repressive means, some of temporal and some others of spiritual kind, concurrently issued by ecclesiastical and civil authorities in order to protect religious orthodoxy and social order, both threatened by theological and social doctrines of heresy."

Bishop of Lincoln, Robert Grosseteste, defined heresy as "an opinion chosen by human perception, created by human reason, founded on the Scriptures, contrary to the teachings of the Church,