Ruskin is referring to the character of Sancho Panzo, a curious blend of shrewdness and credulity, found in Cervantes 's seventeenth-century masterpiece, Don Quixote, a work which derives much of its force, poignancy and humour from the interplay between the hero, a hopeless idealist, and his squire, Sancho, the realist who usually acts from motives of expediency and self-interest.
Ruskin was well-acquainted with the Spanish novel as one of John James Ruskin 's favourites, read aloud to Ruskin as a child: 'at which I could then laugh to ecstasy; now, it is one of the saddest, and, in some things, the most offensive of books to me' ( Works, 35.61). (See Ruskin and Cervantes)