In "The Templar Revelation," authors Lynn Picknett and Clive Prince lay out the clues that lead them to make those bold assertions. They are as diverse as the decorations on Gothic cathedrals, the Gnostic texts discovered in Egypt half a century ago, and works of art from the Renaissance.
It was Leonardo, in fact, who prompted Picknett and Prince to investigate these matters. Their earlier book "Turin Shroud: In Whose Image?" concludes that not only is the Shroud a fake, it was manufactured by da Vinci. They claim he used his secret knowledge of alchemy to concoct a primitive form of photography and create the enigmatic image on the Shroud. Moreover, they claim the face of the "Shroudman" is that of da Vinci himself.
Their research into the Shroud convinced them that Leonardo was a leading member of a mysterious society called The Priory of Sion. They believe the Priory arose in the Middle Ages alongside another secret order, The Knights Templar. Unlike the Templars, however, Picknett and Prince claim the Priory of Sion is alive and well and carefully manipulating events today.
Full story...