Letter to Arthur B. Fuller
p196“But I will not play Mentor much, lest I make you averse to write to your very affte sister MARGARET.”
Fuller, Margaret. The Letters of Margaret Fuller. Edited by Robert N. Hudspeth. Vol. II. Ithaca: Cornell University Press, 1984.
Inferred Fuller's phrase 'play Mentor' is a standard literary allusion to the character Mentor in Homer's Odyssey — Odysseus's old friend who serves as adviser to Telemachus, and through whom Athena acts. The noun 'mentor' had become a generic word for a trusted adviser or guide by the early 19th century, but Fuller's phrasing 'play Mentor' invokes the literary character.