The Cantar de mio Cid is an epic tale about a remarkably successful social climber, offering significant insights into the notion of nobility. The Infantes de Carrión are depicted as part of the upper nobility, possessing extensive land and holding a prestigious position at King Alfonso's court. They wed the Cid's daughters for their wealth but later refer to these unions as "concubinage," suggesting the marriages are invalid due to the considerable class disparity between the Infantes and the Cid.

In medieval Spanish law, individuals of illegitimate birth were unable to marry legally and could only become concubines rather than legitimate spouses. A hint of illegitimacy appears in lines 3377-3381, where Ansur, the Infantes' brother, insinuates that the Cid is the son of a miller. Later romances about the Cid suggest that his father assaulted a miller's wife, resulting in the Cid's birth. This implication of illegitimacy concerning the Cid and his daughters heightens the theme of nobility, particularly when a person of such humble origins gains enough allies and backing to contest the insults hurled at the Cid's family's legitimacy by society's elite. By the poem's conclusion, when we learn that the Cid's daughters marry princes, forming alliances that connect them to future Spanish kings, it becomes clear that the Cid, as a self-made individual, has truly "arrived." Nobility, therefore, is not solely derived from being born into a particular social class. According to the Cid, one can elevate their status through personal achievements. In medieval Spanish society, one way to achieve this is by displaying immense generosity.

A "gift economy" is defined as a system where an individual gains prestige through the act of giving gifts. This type of economy is exemplified by events like the "potlatch" festivals, where leaders of certain Native American tribes in the Pacific Northwest distribute large amounts of wealth and money. In the epic Cid, the protagonist demonstrates his value by giving away his wealth. The narrative includes detailed accounts of the war spoils that the Cid and his followers acquire after battles. The Cid wisely uses his share to send lavish gifts to the king, effectively securing the king's favor. He also shows generosity towards the Church, regularly sending funds to the Abbey of Cardeña to ensure divine favor. Furthermore, he displays kindness even to those he defeats, allowing the inhabitants of a conquered city to return home and releasing Ramón Berenguer, the count of Barcelona, from captivity.

An intriguing exception to the Cid's generosity is his dealings with Rachel and Vidas, the Jewish moneylenders depicted as particularly greedy, whom he seemingly never repays. The Infantes of Carrión, who are portrayed as the Cid's opposites, are known for their lack of noble generosity. By the epic's conclusion, however, the Cid is recognized as a man as honorable as King Alfonso, who admits that the Cid's generosity outshines his own (1.2147). In this society, it is considered more honorable to give than to receive.

Just as generosity defines a noble individual, bravery in combat is also a crucial trait of the ideal hero. The Cid, naturally, exemplifies the courageous warrior, employing strategy and valor to conquer larger armies. Bravery, much like generosity, isn't necessarily tied to one's inherited social rank. The comedic scene where the Infantes de Carrión cower under a couch and behind a wine barrel when a lion escapes highlights the significance of bravery in this epic. The Cid can subdue the lion—a symbol of courage itself—because he possesses exceptional bravery. In contrast, the cowardly Infantes avoid their responsibilities in battle and fabricate lies to conceal their lack...