List of works referred to in abbreviated form. 11 Chapter I: The foundations of mediaeval dualism in the period of late antiquity. 21 Chapter II: The Paulician movement in Byzantium. 32 Chapter III: The rise of a heretical movement in the First Bulgarian Empire. 41 Chapter IV: The Bulgarian Bogomil heresy as portrayed b Cosmas the Presbyter in his Sermon against the Heretics. 50 Chapter V: The Bogomil heresy and Byzantine rr. onasticism. 67 Chapter...