This book explores the foundation of authentic of Christianity from the witness of those in the Upper Room with the Risen Christ and the continuing mystical presence of Christ among his people down the ages. The author charts the disruption of this authenticity by the adoption of Christianity as the State Religion of the Roman Empire and the degree to which that adoption has tended to qualify the Christian Church's loyalty to Christ and thus to become inauthentic even to the point of becoming seriously fake. However, the Church, properly founded on the supernatural reign of Christ, continually recovers its authenticity as its members return to the company of Christ. This book charts this triumph throughout the first millennium of Christian History, and projects it forward into the future and envisages a new and authentic Christianity emerging from the rubble of a discredited State Church.