Boudet's father was the manager[note 3] of the forges of Quillan[note 4] who had been authorized (1837)[9] by François-Denis-Henry-Albert[note 5], Count de La Rochefoucauld-Bayers (1799–1854), a member of a prominent French aristocratic family, the De la Rochefoucault to act as his sole representative to constitute a joint venture, la societé des forges et fonderies d'Axat, a Forge and casting plant, the partnership was also composed of controlling shareholder, Ange-Jean-Michel-Bonaventure (1767–1847), 4th Marquess of Dax d'Axat, once Mayor of Montpellier and his son Barthélémy-Léon-François-Xavîer de Dax.

In 1872, Boudet was transferred to Rennes-les-Bains (succeeding L'abbé Jean Vié who had died a short time earlier) until 1914 when he was discharged from his duty by the Bishop of Carcassonne, Mgr Paul-Félix Beuvain de Beauséjour (1839–1930), due to serious illness.

The name of Henri Boudet's successor was published in the regional Catholic periodical Semaine Religieuse de Carcassonne of 2 May 1914.

For example, when Boudet referred to the location known as The Realsès (today called "la Realsesse") he claimed it was derived from two English words: real (i.e., effective), and cess (tax),[15] when commenting how "The Realsès runs in a valley whose fertile earth enables the inhabitants to pay their taxes and where the Celts till their ground for easy produce".

[17][18][19] Philippe Schrauben, in his introduction to the 1984 re-published edition of Boudet's book, commented: "...we notice that La Vraie langue celtique... is a huge mosaic of extracts of 19th-century works carefully chosen to make them more or less coherent.

[23] Chapters six to eight of Boudet's book consisted of an analysis and mapping of the geological structures surrounding Rennes-les-Bains, whereby he confused isolated large stone blocks, put in place by nature (some marked with naturally-formed Greek crosses, caused by water erosion, as testified by Gibert and Rancoule in 1969 and by others[24][25]), with menhirs and listed them as part of his vast cromlech (Boudet intended to call his tour of the mountain ridges in the area of Rennes-les-Bains with this word), with the inclusion of a secondary stone circle,[26] that was ridiculed by scholars.

[28] Bill Putnam summarized Boudet's central argument: the drunemeton was a "special place where the tribal dignitaries came together to invent these incredible names based on words from a language that had not yet come into existence.

An enthusiastic article on his book was published in the French regional Newspaper Le Courrier de l'Aude of 18 December 1866,[30] praising his pioneer work, followed shortly afterwards by a severely negative review, given by lawyer and historian Gaston Jourdanne (1858–1905)[note 10], published in the French Newspaper Le Radical du Midi of 26 May 1887 that questioned the seriousness of Boudet's self-satisfied book.

Boudet made an unsuccessful attempt to have his book honoured by the award of the médaille d'or, a prize (the awardee received a sum of money) distributed by the Académie des sciences, inscriptions et belles-lettres de Toulouse.

The Academy, while recognizing that an amount of work has gone into this volume which does deserve some respect, does not believe that it has a duty to set its seal of approval, by awarding a prize, on a system of historical reconstruction that is as bold as it is novel'."

[36] Unsympathetic to Boudet's works, Cartailhac asked the local archeologists to be cautious about the claims of a gullible priest, author he said of the ridiculous book La Vrai langue celtique.

In 1893, Cartailhac's notice was used by Gaston Jourdanne for his introduction[37] of Boudet's book to the Société d'Etudes Scientifiques de l'Aude.

Citing various renowned authorities, including a work by his friend, a well known Celtic expert, Marie Henri d'Arbois de Jubainville, Jourdanne demonstrated the errors of Boudet's researches and conclusions.

Abbé Ancé then conducted an excavation in a part of his town and discovered some ancient graves possibly dating back to Neolithic times, as well as some artifacts (that were donated to the Museum of Carcassonne).

Bordes-Pagès made some additions of his own to Boudets's La Vraie langue celtique et le cromleck de Rennes-les-Bains.

My noble lord is very interested in linguistic and ethnographic studies and highly appreciates the information that you have sent him, and will be happy to know the outcome of your future researches and discoveries".

Some Rennes-le-Château researchers are inclined to identify the BS monogram inscribed on the statue of the Devil supporting the Holy Water Stoup, located at the entrance to the church of Rennes-le-Château, with the surname initials of Boudet and Saunière or the names of two local rivers, the Blanque and the Sals (as first envisaged by Gérard de Sède in 1967[56][57]), but there is no concrete evidence as to what the inscription actually means and remains undeciphered.

[58] Because Henri Boudet was Abbé of Rennes-les-Bains at the same period of time that Bérenger Saunière was incumbent at Rennes-le-Château, also for being the author of La Vraie langue celtique, he has become a central character in modern conspiracy theories.

De Sède interpreted the Church of Rennes-les-Bains and its churchyard also as part of a secret code, that led to and involved Rennes-le-Château.

[6] In his 1988 book entitled, Rennes-le-Château; Le dossier, les impostures, les phantasmes, les hypothèses, de Sède affirmed once again that Boudet wrote La Vraie langue celtique et le cromleck de Rennes-les-Bains in a cryptic fashion, adding to his 1967 analysis that Boudet used Jonathan Swift's A Discourse to Prove the Antiquity of the English Tongue, Showing from various instances, that Hebrew, Greek, and Latin were derived from the English (1712) [64] and his Ars Punica, sive flos lingarum; The Art of Punning or the flower of languages in 79 rules (1719) as a method of encryption.