Fascinated from an early age by the paintings of Poussin, Leonardo and other great masters, Peter Blake has watched as others have made guesses as to their meanings, even linking them to the mysteries surrounding the French village of Rennes-le-Chateau - at the core of the seminal " Holy Blood, Holy Grail" . But from the recurrent geometrical themes Blake has discerned in the paintings, he reaches quite different conclusions from those grasped at by other researchers. For instance, by overlaying the grids found in key paintings of both Poussin and Leonardo on maps of the Langeudoc, he has pinpointed a never-before-discovered hill tomb. If the clues that have lead him this far on the trail are right, this could be the final resting place of two of the most significant characters from the Bible. But the fact that the tomb exists is only a starting point. Through following the trail by which he found it we unravel a rich cloth of learning and religion spun in secrecy over the centuries, and uncover the true identity of a host of remarkable historical characters, all party to the secret of the ciphers - from popes and painters to the real Man in the Iron Mask.