Ermance de la Jonchére Dufaux was born on 8 March 1839 in Cambrai, France and died in Suresne (Hauts-de-Seine) on 3 March 1915. Ermance's father was a wealthy wine and wheat producer. Traditionally, the Dufaux family lived in a medieval castle, inherited from their ancestors.

In 1853, the Dufauxs' daughter began to show disturbing nervous imbalances and premonitions. Because of this problem, her father went to the famous doctor Cléver De Maldigny.

According to Mr. Dufaux's account, the doctor said that Ermance seemed to be suffering from a new nervous disorder that had claimed several victims in America and was now reaching Europe. Victims of the disease went into a kind of hysterical trance and began to receive hypothetical messages from beyond the grave.

The doctor advised Mr. Dufaux to take Ermance to his surgery as soon as possible. This was done. A few days later, the young woman kept her appointment.

Maldigny put a pencil in the young woman's hand and asked her to write down what she had been told. Ermance began to laugh and joke, but suddenly her arm took on a life of its own and began to write on its own. Finding herself overpowered by a strange force, Ermance became frightened, dropped the pencil and did not want to continue the experiment. 

Maldigny examined the paper and confirmed his diagnosis. Ermance's parents were very worried. As the family was famous at court, the news soon spread through Paris and Fontainebleau, reaching the ears of the Marquis de Mirvile, a famous scholar of magnetism.

The marquis visited the Dufaux castle and asked to examine Ermance. Her parents agreed, but the girl had to be convinced. Finally, Ermance was able to write and Mirvile asked the invisible one:

– Is the spirit I am thinking of present? If so, please write your name through the child.

Ermance's hand began to move and she wrote:

– No, but one of your remote relatives.

– Can you write your name?

– I prefer my name to come directly to your mind. Think for a moment.

– Saint Louis, King of France, cousin of the first nobleman of my family?

– Yes, that's me.

– Can Your Majesty prove to me that you really are our great king?

– No one in this house knows that you and your relatives consider me the family's Guardian Angel.

Maligny saw Ermance's case as an illness, but the marquis also had his preconceived explanations. In his opinion, she was only picking up ideas and thoughts from her surroundings. That was at best. At worst, the young woman was being interpreted by the Devil, because, as a Catholic, he did not believe that the dead could communicate. The Paris Academy of Sciences was to make a conclusive analysis.

Mr. Dufaux, however, took the case no further. Although he was also a Catholic, he preferred to believe that his daughter was neither ill nor possessed, but simply an intermediary between the living and the dead. The family became accustomed to the fact and Ermance's faculty came to be seen as something natural and positive.

Her contacts with Saint Louis became frequent. Under his influence, she wrote the posthumous autobiography of the canonised king, entitled "The History of Louis IX, dictated by himself". In 1854, this text was published in book form, but the censors of Napoleon III's government forbade its distribution. The censors considered that some passages could be understood as a criticism of the Emperor and the Church.

The Dufauxs' favourable position towards neo-spiritualism provoked reprisals. In a confession, Ermance refused to deny her belief in spirits, attributing her messages to Satan, and was forbidden to take communion. The Empress also cooled her relationship with her family. However, Emperor Napoleon III became curious and asked to meet Mademoiselle Dufaux.

She was received at the palace of Fontainebleau and received a message from Napoleon Bonaparte for her nephew. The message was in response to a mental question from Louis Napoleon, and its style corresponded exactly to that of Bonaparte.

In time, the spirits also began to speak through Ermance. In 1855, at the age of 14, Ermance published her second ‘spiritualist’ book (at that time the terms spiritist, medium, etc. did not exist). The first to be distributed and sold: ‘The story of Joan of Arc, dictated by herself’ (Meluu Publishers, Paris).

According to Canuto Abreu, the Dufaux family met Allan Kardec on the evening of 18 April 1857. The codifier offered a small reception in his flat and the Dufauxs were brought by Madame Planemaison, a great friend of the Lyonnais professor.

At the end of the meeting, Ermance received a beautiful message from St. Louis, who from then on would become a kind of spiritual supervisor of the Master's work. According to the old king, Ermance, like Kardec, was a reincarnated druidess. The ties between the two became closer and she became the main medium for Prof. Rivail's home meetings.

At the end of 1857, Kardec had the idea of publishing a spiritist magazine and wanted to know the opinion of the spirit guides. Ermance was the medium chosen and, through her, a spirit gave the Master of Lyon some excellent advice. The organ was called "Spiritist Magazine" and was launched in January of the following year.

As Allan Kardec's flat was too small for the large number of people attending his meeting, some of the participants decided to rent larger premises.

But for this they needed legal authorisation. Mr. Dufaux took it upon himself to obtain the approval of the authorities, achieving in fifteen days what would normally take three months. Once the authorisation was granted, the Codifier and his disciples founded the Parisian Society of Spiritist Studies in April 1858. Ermance was one of the founding members.

During 1858, Ermance received two more mediumistic autobiographies. This time, the authors were the French kings Louis XI and Charles VIII. The Codifier praised Miss Dufaux's work and transcribed extracts from "Confessions of Louis XI" in the Spiritist Review. That same year, Kardec published three psychographed messages by the young medium. We have no news about the possible publication of Charles VIII's memoirs.

Canuto Abreu revealed that Rivail used her as a medium to revise the second edition of The Spirits' Book.

In 1859, Ermance was no longer mentioned as a member of the SPEE in the pages of Kardec's monthly journal. This leads us to believe that he had left the Society. Another indication of this supposition is that St. Louis began to communicate through other sensitives (Mr. Rose, Mr. Collin, Mrs. Costel and Miss Huet). There is also no record that his work continued in other groups.

What happened to Ermance, had she married and abandoned militancy, like Ruth Japhet and the Baudin girls, had she fallen out with Kardec, had she left France, had she become discouraged with the spiritism? These are questions that only she could answer. Be that as it may, the Codifier continued to make his work known. In 1860, he announced the re-publication of "The Story of Joan of Arc dictated by herself" by the Lendoyen bookshop in Paris.

In 1861, she sent several copies of this book, together with her works, to the French publisher Maurice Lachâtre, who was in exile in Barcelona. The aim was to make Spiritism known on Spanish soil. These volumes were confiscated and burned in the public square by the Catholic Church in the famous Auto-de-fé of Barcelona.

«The History of Louis IX dictated by himself» was released by the Censorship and finally published by the Paris magazine La Verité in 1864. In early 1997, the Brazilian publisher Edições LFU translated «The Story of Joan of Arc» into Portuguese.