The " Saint-Clair " part of his surname was added to his real surname on the basis that this was the family name associated with the area of Gisors associated with his hoax-according to the mythology of the Priory of Sion " Jean VI des Plantard " married a member of the House of Gisors during the 12th century.

Plantard originally claimed these genealogies had been compiled by a Doctor Hervé and Abbé Pichon ( 1828 – 1905 ), originally at the request of Napoleon Bonaparte, who found out about the Merovingian survival from Abbé Sieyrès.

By 1978 Plantard began claiming that his grandfather had met Bérenger Saunière in Rennes-le-Château, and that the real source of Saunière's wealth was the Abbé Henri Boudet, parish priest of the nearby village of Rennes-les-Bains.

The book was later revealed to be based on a hoax originating with Pierre Plantard in the mid-20th century.

* Pierre Plantard, the mastermind behind the Priory of Sion hoax who claimed to be Merovingian, a pretender to the throne of France.

Pierre Plantard, the creator of the Priory of Sion mythology, tried to argue that the sepulchre at Les Pontils was a " prototype " for Poussin's painting, but it was situated directly opposite a farmhouse ( behind the foliage ) and was not in the " middle of nowhere " in the French countryside, as is commonly assumed.

The precursor to these Rosslyn theories is the 1982 book The Holy Blood and the Holy Grail by Michael Baigent, Richard Leigh and Henry Lincoln that introduced the theory of the Jesus bloodline in relation to the Priory of Sion hoax-the main protagonist of which was Pierre Plantard, who for a time adopted the name Pierre Plantard de Saint-Clair.

Pierre Athanase Marie Plantard ( 18 March 1920 – 3 February 2000 ) was a French draughtsman, best known for being the principal perpetrator of the Priory of Sion hoax, by which he claimed from the 1960s onwards that he was a Merovingian descendant of Dagobert II and the " Great Monarch " prophesied by Nostradamus.

Pierre Plantard was born in 1920, in Paris, the son of a butler and a concierge ( described as a cook for wealthy families in police reports of the 1940s ).

According to a police report on the Alpha Galates dated 13 February 1945 the organisation was only composed of at most 50 members, who resigned one after the other as soon as they sized up the president of the association ( Pierre Plantard ) and figured out that it was not a serious enterprise.

According to the late Robert Amadou ( 1924 – 2006 ), Pierre Plantard in 1953 was accused of selling degrees of esoteric orders for exorbitant sums.

French researchers dispute the connection between Robert Amadou and Pierre Plantard.

On 25 June 1956, Pierre Plantard and André Bonhomme legally registered in the town of St Julien-en-Genevois a new association called the Priory of Sion, based in Annemasse close to the French border near Geneva.

But it was due to the success of de Sède's book L ' Or de Rennes that Pierre Plantard became famous, as the guardian of the secret of Rennes-le-Château.

In 1989, when Plantard revised his claims about the Priory of Sion, it was stated in a 1989 issue of Vaincre: " The parchments of Blanche of Castile were in Etienne Plantard's safe-deposit box in London since November 1955 and they did not ' mention ' Dagobert, or a Dagobert II and Pierre Plantard de Saint-Clair was never ' a Merovingian pretender ' to the throne of France: His lineage results from the Counts de Rhédae and by the female line of Saint Clair-sur-Epte, which has no relationship with ' Sinclair '.

From 1975 Pierre Plantard used the surname Plantard de Saint-Clair, described as an epithet by Jean-Luc Chaumeil, following his interview with Plantard in the magazine l ’ Ère d ’ Aquarius.

Pierre Plantard was hypothesised as the direct descendant of Jesus Christ.

This initiative by Plantard had an unexpected consequence ; in October 1993, the judge investigating the Pelat scandal had Pierre Plantard's house searched.

* Chaumeil-Plantard, second part of an interview of Jean-Luc Chaumeil where he mentions his discovery of the bewitched hill and the owner of the abbé's estate, Henri Buthion, as well as his tumultuous relations with Pierre Plantard, Gérard de Sède and Mathieu Paoli

da: Pierre Plantard

When Jean-Luc Chaumeil revealed during the 1980s that Plantard's genealogical claims were fictional adaptations of Louis Saurel's article published in 1960, Plantard released a " cheque " dated 14 April 1960 showing his former wife Anne-Léa Hisler had been paid for the article contained in Les Cahiers de l ' Histoire, and therefore claiming she was the original author.

De Chérisey also chose to copy material from Vigouroux because he was a priest connected with the Church of St Sulpice, a location that had been exploited as part of the Priory of Sion myths as created by Plantard and de Chérisey, so de Chérisey's utilisation of this priest fitted in nicely into these myths.

Plantard also claimed that the phrase " Et In Arcadia Ego " had been the motto on his Family Coat-of-Arms for generations.

On 21 April 1941 Plantard wrote to the Paris Prefect of Police that his group the French National Renewal was to take possession of the unoccupied premises located at 22 place Malesherbes, 1st floor " which are currently let to an English Jew, Mr. Shapiro, who is presently fighting alongside his fellows in the British armed forces.

" By 1942 Plantard wanted to form another association, the Alpha Galates, membership prohibited to Jews, but the occupying German authorities refused permission.

At the same time Plantard worked as a draughtsman for the company établissements Chanovin.

According to a more reliable source, given in a letter written by Léon Guersillon the Mayor of Annemasse in 1956, contained in the folder holding the 1956 Statutes of the Priory of Sion in the subprefecture of Saint-Julien-en-Genevois, Plantard was given a six-month sentence in December 1953 for abus de confiance ( breach of trust ), relating to other crimes.

In 1959, Plantard edited a second series of the journal Circuit, subtitled Publication Périodique Culturelle de la Fédération des Forces Françaises.

It was in this second series of Circuit that Plantard claimed he received a letter from de Gaulle dated 27 June 1959.

Louis Vazart referred to a letter dated 29 July 1958, also referring to another letter from de Gaulle dated 3 August 1958 where he thanked Plantard for his support during the Algerian crisis.

Plantard read the article and wrote to de Sède, later collaborating with him on the book Les Templiers sont parmi nous, ou, L ' Enigme de Gisors (" The Templars are Amongst Us, or The Enigma of Gisors "), that was published in 1962.

This inspired Plantard to write his own book on the subject matter but, failing to find a publisher his manuscript was extensively rewritten by Gérard de Sède resulting in the 1967 book, L ' Or de Rennes.

The book adapted Corbu's story to fit-in with Plantard's claims about the survival of the line of Merovingian king Dagobert II, and Plantard began claiming to be descended from Dagobert II since 1964 when he began depositing false documents in the Bibliothèque nationale giving the secret history of the Priory of Sion.

By 1958, Plantard was back living in Paris where he was actively supporting General de Gaulle, establishing a Committee of Public Safety ( based in Paris ) during the Algerian Crisis using the name " Captain Way ".

In a letter dated 4 April 1989, Plantard wrote that Victor Hugo " drew up the constitutions of the Priory of Sion on 14 July 1870, on the same day that he planted the oak-tree of the United States of Europe ".

The search failed to find any documents related to Pelat., but turned up a hoard of false documents, including some proclaiming Plantard the true king of France.

In a 2005 TV documentary, de Sede's son Arnaud stated categorically that his father and Plantard had made up the existence of the Priory of Sion — to quote Arnaud de Sède in the programme, " it is absolute piffle ".

According to the genealogies in the Dossiers Secrets his sister married one " Jean des Plantard ".

The book L ' Or de Rennes by Gérard de Sède ( with the collaboration of Pierre Plantard ) contained elements relating to the fictitious secret society the Priory of Sion, reproducing " parchments " that alluded to the survival of the Merovingian line of Frankish kings from Dagobert II, and Pierre Plantard claimed to be descended from that monarch.

The parchments hinted at the survival of the line of the Frankish king Dagobert II, that Plantard claimed to be descended from, as well as attempting to verify the existence of the 1000-year-old secret society, the Priory of Sion.

In 1990, Plantard revised himself by claiming he was only descended from a cadet branch of the line of Dagobert II, while arguing that the direct descendant was really Otto von Habsburg, actually descended from Sigebert I ( nicknamed " Plant-Ard "), different to Sigebert IV, who was the son of Bera II and the grandson of Wamba, the founding father of the House of Habsburg and also the builder of Habsburg Castle, drawing on content found in a 1979 book by Jean-Luc Chaumeil.