Traditionally, historical documents have been read and interpreted at face value. However, in the intro to this fascinating book first published in 1912, Harold Bayley suggests historians should also hold these text up to the light to read the deep symbolism of the myriad watermarks embedded under the surface. 'These emblems', he argues, 'are thought fossils in which lie enshrined the aspirations and traditions of the numerous mystic and Puritanic sects of the Middle Ages.'