The three main characters are clearly Mary herself, Godwin, and Shelley, and their relations can easily be reassorted to correspond with actuality.
Highly personal as the story was, Mary Shelley hoped that it would be published, evidently believing that the characters and the situations were sufficiently disguised.

In May of 1820 she sent it to England by her friends, the Gisbornes, with a request that her father would arrange for its publication.

But _Mathilda_, together with its rough draft entitled _The Fields of Fancy_, remained unpublished among the Shelley papers.

Although Mary's references to it in her letters and journal aroused some curiosity among scholars, it also remained unexamined until comparatively recently.
This seeming neglect was due partly to the circumstances attending the distribution of the family papers after the deaths of Sir Percy and Lady Shelley.

One part of them went to the Bodleian Library to become a reserved collection which, by the terms of Lady Shelley's will, was opened to scholars only under definite restrictions.