Shelley's mentor Godwin had three highly educated daughters, two of whom, Fanny Imlay and Claire Clairmont , were his adopted step-daughters. Godwin's first wife, the celebrated feminist Mary Wollstonecraft , author of A Vindication of the Rights of Woman , had died giving birth to Godwin's biological daughter Mary Wollstonecraft Godwin , named after her mother. Fanny was the illegitimate daughter of Mary Wollstonecraft and her lover, the diplomat speculator and writer, Gilbert Imlay . Claire was the illegitimate daughter of Godwin's much younger second wife, Mary Jane Clairmont Godwin, whom Shelley considered a vulgar woman—"not a proper person to form the mind of a young girl", he is supposed to have said,  and Sir John Lethbridge . The brilliant Mary was being educated in Scotland when Shelley first became acquainted with the Godwin family. When she returned, Shelley fell madly in love with her, repeatedly threatening to commit suicide if she did not return his affections.