What does the Holy Grail represent? What did it represent to Rh negatives in the past? Since the 19th century, the Holy Grail has been linked to various conspiracy theories. In 1818, Austrian pseudohistorical writer Joseph von Hammer-Purgstall connected the Grail to contemporary myths surrounding the Knights Templar that cast the order as a secret society dedicated to mystical knowledge and relics. In Hammer-Purgstall’s work, the Grail is not a physical relic but a symbol of the secret knowledge that the Templars sought. There is no historical evidence linking the Templars to a search for the Grail, but subsequent writers have elaborated on the Templar theories.