Who do you picture as Rosamund?
With her violet eyes, whom Eleanor "didn't poison"?
I tend to picture Elizabeth Taylor -- whose middle name is, indeed, Rosemond.
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You do make a good point, but Taylor is a too strong of a persona for Rosamund. I image her as the opposite of Eleanor. Meek, quiet, obedient and devoid of any real power or ambition. That's why I cant see Taylor as her. Some pretty blond unknown.
"Flash, Flash, I love you, but we only have fourteen hours to save the Earth!"