 When she returned, Shelley fell madly in love with her, repeatedly threatening to commit suicide if she did not return his affections.On 28 July 1814 Shelley abandoned Harriet, now pregnant with their son Charles (November 18141826) and (in imitation of the hero of one of Godwin's novels) he ran away to Switzerland with Mary, then 16, inviting her stepsister Claire Clairmont (also 16) along because she could speak French.The older sister Fanny was left behind, to her great dismay, for she, too, may have fallen in love with Shelley.