E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Duke and Duchess
in Don Quixote, who play so many tricks on the Knight of the Woeful Countenance, were Don Carlos de Borja, Count of Ficallo, who married Donnia Maria of Aragon, Duchess of Villahermora, in whose right
the count had extensive estates on the banks of the Ebro; among others he had a country seat called Buenavia, which was the place Cervantes referred to.