In 1956, a French draftsman named Pierre Plantard officially registered a modest localized association named the Priory of Sion, originally intended to advocate for low-cost housing in Annemasse. However, over the subsequent decade, Plantard transformed this mundane group into an elaborate esoteric myth. Seeking personal prestige and monarchical status, Plantard, alongside his accomplice Philippe de Chérisey, created a series of fabricated historical documents known as the Secret Files of Henri Lobineau.
Between 1964 and 1967, Plantard quietly deposited these forged genealogical charts and pseudo-ancient parchments into the National Library of France in Paris. The planted documents claimed that the Priory of Sion was a powerful secret society founded in 1099 during the First Crusade to guard a profound secret: the Merovingian royal dynasty was descended directly from Jesus Christ and Mary Magdalene. Plantard positioned himself as a direct descendant of Merovingian King Dagobert II and the legitimate heir to the French throne.
The hoax gained massive international visibility when British researchers used the forged archive as central evidence for their 1982 bestseller The Holy Blood and the Holy Grail, which later served as the primary foundation for Dan Brown's mega-hit novel The Da Vinci Code. The grand deception crumbled in 1993 during a judicial investigation into financial misconduct involving French businessman Roger-Patrice Pelat. Placed under oath by a French judge, Plantard admitted under interrogation to inventing the entire story and forging every document, exposing one of the twentieth century's most successful cultural fabrications.