"the treachery of Vellido and the deceit of Ganelon"
According to Spanish chronicles, and the legend propagated by various romances, Vellido Dolfos was a Galician noble who assassinated King Sancho II of Castile in 1072. Ganelon is the knight who betrays Charlemagne's army to the Muslims in the epic poem The Song of Roland
. The casual mingling of figures from history and fiction, by Dorotea here and other characters throughout the book, suggests how confused the two were in the broader culture of the time - not only in Don Quixote's head.
Online edition of 'The Song of Roland' as translated by Charles Scott Moncrief (London 1919)
Online edition of the 'Chronicle of the Cid' as translated by Robert Southey (London, 1808) from several Spanish sources, including an account of Sancho's death