Chivalry: Expectation vs. Reality
The concept of chivalry and the chivalric code that Duncan lives by and upholds versus how it is actually lived out by others in the Seven Kingdoms is perhaps the most pervasive theme in the series. His code of ethics affects every decision and interaction that he makes and as such it also becomes instrumental in forming the mental, emotional, and social framework of Aegon who would become king in the years to come, affecting his decisions and actions many years into the future. Unfortunately though Duncan and Aegon seem to be the only one concerned with following the actual code of the knight, everyone else--knights and feudal lords included--seems to think that the code is simply a set of loose guidelines rather than a body of principles to follow strictly. Despite few people sticking to the code the Dunk does, he keeps to the code seeing it as a way of defining his identity and making sense of the world around him rather than seeing it as a list of restrictions that keep him from enjoying himself.
Class Divisions
Class division functions both as a plot device and as a recurring theme in the series. The Seven Kingdoms are patterned heavily after medieval Europe, an age where class divisions are the done deal. The idea that a poor knight could become a mentor and moral authority to a prince is both a novelty and a breaking of social norms that the other characters in the novella series find both refreshing and encouraging. This is also the reason that Dunk gains the lasting respect of people he comes into contact with, there is such a large dissonance in his station in life versus the nobility he displays; whereas the opposite is typically true of both the so called nobility and the low-born--many respond act with a crassness and churlishness completely unexpected from people of their particular “station in life”. The small folk look up to Dunk because he’s a working-class hero, the poor guy who did good but more than that he actually lives out the knightly ideal of defending the downtrodden and upholding the honor of women.
Duty vs. Morals
The code of a knight, on more than one occasion and among several characters in the series, has come into conflict with the commands issued by a feudal lord that he has come to serve. This conflict between a knight’s moral code of and the fulfillment of his duties is both a recurring theme and a plot driver throughout the series. Ser Duncan, in swearing allegiance to Ser Eustace Osgrey to fight on his behalf against the Webbers, unwittingly throws in his lot with participants of the Blackfyre Rebellion. In doing this, he also unwittingly earns the hate of Lady Rohanne as he now participates in a battle that had ultimately claimed the love of her life. Ser Duncan’s commitment to his knightly vow of protecting the weak is also tested in this support of Ser Eustace’s cause, as his squabble with the Webbers will ultimately have the common folk drafted to fight in his war. Dunk’s upholding of the code of chivalry to defend Tanselle’s honor ends up with him punching the villainous Aerion which set into motion events that affect the entirety of the Seven Kingdoms.