Thus Mary took all the blame for the rift with Shelley upon herself and transferred the physical alienation to the break in sympathy with Godwin. That she turned these facts into a story of incest is undoubtedly due to the interest which she and Shelley felt in the subject at this time. They regarded it as a dramatic and effective theme. In August of 1819 Shelley completed _The Cenci_. During its progress he had talked over with Mary the arrangement of scenes; he had even suggested at the outset that she write the tragedy herself. And about a year earlier he had been urging upon her a translation of Alfieri’s _Myrrha_. Thomas Medwin, indeed, thought that the story which she was writing in 1819 was specifically based on _Myrrha_. That she was thinking of that tragedy while writing _Mathilda_ is evident from her effective use of it at one of the crises in the tale. And perhaps she was remembering her own handling of the theme when she wrote the biographical sketch of Alfieri for Lardner’s _Cabinet Cyclopaedia_ nearly twenty years later. She then spoke of the difficulties inherent in such a subject, “inequality of age adding to the unnatural incest. To shed any interest over such an attachment, the dramatist ought to adorn the father with such youthful attributes as would be by no means contrary to probability.”[xvii] This she endeavored to do in _Mathilda_ (aided indeed by the fact that the situation was the reverse of that in _Myrrha_). Mathilda’s father was young: he married before he was twenty. When he returned to Mathilda, he still showed “the ardour and freshness of feeling incident to youth.” He lived in the past and saw his dead wife reincarnated in his daughter. Thus Mary attempts to validate the situation and make it “by no means contrary to probability.”