Priory of Scion

The Priory of Sion is a name given to multiple groups, both real and fictitious. The most notorious is a fringe fraternal organization, founded by Pierre Plantard in 1956. In the 1960s, Plantard created a fictitious history for that organization, describing it as a secret society founded in the Kingdom of Jerusalem in 1099, which serves the interests of the Merovingian dynasty and its alleged bloodlines. This myth was expanded upon and popularized by the 1982 controversial book The Holy Blood and the Holy Grail, and later claimed as factual in the preface of the 2003 conspiracy fiction novel The Da Vinci Code. Even though the Priory of Scion was mainly fake, many conspiracy theorists persist in believing that the Priory of Scion still hides a secret.

http://www.fiu.edu/~mizrachs/poseur3.html