Don Quixote Volume 2, Chapter 16
As Don Quijote and Sancho travel on, Sancho begins to believe he had truly seen his friend from home. Don Quijote asks him to listen to reason -- why would the real Samson Carrasco behave in such a manner? Also, if these evil magicians can alter Dulcinea's beauty to homeliness, they surely could alter enemies to take on the appearance of friends.
A man, beautifully outfitted and wearing a green overcoat, rides past them and Don Quijote offers him to journey with them if he is going the same way. The man says he would be glad to if they are sure his mare will not disturb his horse. They assure him that aside for one incident, Rocinante can be trusted. Don Quijote becomes aware of the man's frank appraisal of him (the man is taking in Don Quijote's strange appearance) and informs him that he is none other that that celebrated knight Don Quijote of whose life thirty thousand books have been printed. The man says that his literary tastes lean toward non-fiction and has never read tales of chivalry. He introduces himself as Don Diego de Miranda.
It turns out the man has a son who insists on being a poet, which is a bit of a disappointment to his father. Don Quijote waxes eloquently on poetry and poets, impressing Don Diego who begins to doubt his first impression of Don Quijote (that he's insane) and revise his opinion of him. Meanwhile, Sancho is buying cottage cheese from some shepherds he spotted. A cart bearing royal flags is approaching and Don Quijote tells Sancho to fetch his helmet.