No man is a hero to his valet.

[Il n’y a pas de grand homme pour son valet-de-chambre.]

Anne-Marie Bigot de Cornuel (1605–1694) French wit and aphorist

Lettres de Mlle Aïssé, 12.13 (1728)
    (Source)

See Montaigne (1586), Goethe (1805).

For discussion on this and related quotes, see here.