Just as Don Quixote wishes to inform the duke and duchess of his plans to take up his active life as a knight-errant, he is interrupted by the appearance of Donna Rodriguez and her daughter, both dressed in black. The duke and duchess are also surprised for they realize that the duenna is seriously asking the knight for assistance. In answer, Don Quixote vows to challenge the daughter's false lover, either slaying the offender or forcing him to marry the betrayed maiden. Promptly the duke accepts the challenge in the name of his vassal and announces the time and place of combat. The page now returns from his visit to Teresa Panza, and with great amusement, the duchess reads Teresa's letter out loud. Don Quixote now reads to them Teresa's letter to Sancho, and the company enjoys the homely style, the gossip from town, and the expressed joy of the wife at her husband's exalted position. Lastly, Don Quixote reads Sancho's letter, and the hearers are startled to discover such wisdom in the governor whom all took for a fool.
The clever steward best expresses the theme of these chapters of Don Quixote's "martyrdom," when he tells Governor Sancho: "Every day produces some new wonder, jests are turned into earnest, and those who designed to laugh at others, happen to be laughed at themselves." As the duke and duchess continue with their extravagant entertainments, the knight seems to increase in stature, while they themselves appear fools. Instead of making Don Quixote ridiculous, his humiliating experiences enhance his nobility and exalt his purity of purpose. Sancho is given the opportunity to practice a responsible ethic he never realized he possessed, while Teresa Panza, with her spontaneous and genuine feelings, is favorably contrasted with the duchess. Closing the full cycle, Cervantes shows that the perpetrators of the joke are themselves the subject of ridicule, that madmen are sane in contrast to normal people, and that fools are best capable of great wisdom.