The Oracle Glass is set in 17th century Paris and Versailles surrounding the court of the sun king Louis XIV. The novel surrounds the life of a young girl named Genevieve Pasquier who is born with a crooked spine and deformed leg. After the death of her father and being assaulted she contemplates suicide before she is rescued by the infamous and notorious historical figure Catherine Monviosin also known as La Viosin. This sorceress and abortionist takes her under her wing and teaches her the ropes of fortune teling. Genevieve Pasquier learns how to read the oracle glass and divine water visions. She uses her gift to read fortunes for the illustrious courtiers of Versailles including Madame de Montespan the mistress of Louis XIV. In the novel the black masses performed by La Viosin are depicted in all of their horrific detail. Genevieve struggles to find her true love and it might not be the man whom she thought it would be. Will she end up with her true love at the end of the book? Better yet…will she survive the danger that surrounds her?
Catherine Monvoisin known as La Voisin was a fortune teller, abortionist and an alleged sorceress that lived during Louis XIV’s reign at Versailles. She was a chief participant in the affair of the poisons. It is suspected that she killed between 1000-2500 people, mostly children in black masses. These children were allegedly taken from orphanages and purchased from the poor. La Viosin began her fortune telling after her husband was ruined as a jeweler. Around 1665 La Viosin was questioned by the catholic church regarding her fortune telling and successfully defended herself. Of course, it helps that the Abbe Guiborg was performing black masses with her which he admitted before his imprisonment. La Viosin sold love powders with alleged horrifying ingredients including the dust of human remains, bones of toads, Spanish flies, and teeth of moles etc. Her most important client was Madame de Montespan who was said to have served as the living altar in the black mass where a bowl was placed on her stomach and a baby was sacrificed and its blood poured into the bowl. Catherine La Viosin was arrested and burned at the stake for attempting to poison the king with a poisoned petition. Allegedly Madame de Montespan wanted to poison the king after he entered into a relationship with Angelique de Fontanges. Although Madame de Montespan was never implicated the king never took her to his bed again after the charges alleged against in her in the affair of the poisons.
Catherine Monvoisin and the priest Étienne Guibourg are shown performing a black mass for Madame de Montespan in an 1895 engraving by Henry de Malvost.