What is the relationship between Don Quixote and Sancho Panza in Don Quixote de la Mancha?

Don Quixote is searching for love and beauty, but
unfortunately, all his attempts to make world better do only harm to those he meets.
Until his final illness, Don Quixote remains true to his chivalric conception of right
and wrong. Even though his mind clears enough to see that the inns he sees are just
inns, not the castles as he used to believe, and windmills are not the dragons as he
previously imagined, he never stopped thinking that Dulcinea can save him from
misfortune.  Despite his delusions, Don Quixote is intelligent and from time to time
seemingly sane.

Don Quixote’s split between his
madness and his common sense. Don Quixote’s character remains versatile throughout the
whole story.

Despite all his madness, he leaves absolutely
positive impression. Of course, character of Don Quixote would be not as colorful as it
is without his companion Sancho Panza. He is a simple peasant who follows Don Quixote
out of greed and curiosity. Sancho lives somewhere in between Don Quixote’s imaginable
world and the world of his contemporaries, he is able to co-exist in both of them.
Sancho Panza represents the good and the bad features of the current era of chivalry, he
has the negative side, but he also possesses the honorable features that the other sane
characters largely lack. At the beginning of the novel Sancho appears like the
contemporaries against whom Don Quixote rebels, he eventually becomes the character with
the most varied perspective and the most wisdom, learning from the world around him
thanks to his constant curiosity. Sancho observes and thinks about Don Quixote enabling
us to judge him, he is a link that connects us with Don Quixote’s imaginary world.
Sancho Panza is the hero who humanizes story, who brings humor and compassion as well as
dignity and devotion. Though Sancho is ignorant, foolish, illiterate, and cowardly, ha
also proves himself as a wise and compassionate, being a better companion than
aristocratic and educated Duke. Through Sancho Panza Cervantes critiques the
ill-conceived education of class and worth. Sancho gains confidence in himself and
ability to solve problems despite his lower-class status. Sancho, as opposed to Don
Quixote , usually symbolizes realism. Sancho is also comic relief throughout the novel.
He finally returns to his wife and kids at the end, after Quixote has resigned as a
knight-errant.

The struggle between imaginary world and
real one is illustrated in  Cervantes’ novel, Don Quixote. Through the characters of Don
Quixote and Sancho Panza, Cervantes illustrates the challenges one faces while balancing
between idealism and rationalism. His portrayal of Don Quixote’s foolishness in his
knightly adventures also illustrates a kind of futility. Depicting both Quixote’s and
Panza’s characters, Cervantes reveals that it is worthless to only adopt a single way of
thinking. The two ends of idealism and rationalism must co-exist in person’s
life.