Translations for myth in French

Here are paragraphs from public domain books translated:

"Just one hint to you, Lestrade," drawled Holmes, before his rival vanished; "I will tell you the true solution of the matter. Lady St. Simon is a myth. There is not, and there never has been, any such person."	— Écoutez, Lestrade : un mot seulement ; je vais vous donner la vraie solution. Lady Saint Simon est un mythe. Il n’y a pas de lady Saint Simon et il n’y en a jamais eu.
The Adventures of Sherlock Holmes, by Arthur Conan Doyle	Les Aventures de Sherlock Holmes, de Arthur Conan Doyle