At its most basic, The Song of Roland is an adventure story of heroic knightly battle. However, it also portrays the values and practices of a society governed by chivalry, and it establishes characters with distinctive personality traits who either do or do not live by those values and whose moral substance is determined thereby. Chivalry becomes a feature of narrative suspense in the text because of the subplot of courtly intrigue and jealous rivalry in Roland's somewhat dysfunctional family. Furthermore, the poem brings in religious themes linked to the culture of the Crusades, with Christianity being arrayed against Islam and constantly under attack--only to triumph eventually.
It may be useful to discuss the last-named aspect of SR first. The setting of the story is several hundred years before the Crusades were launched, but it is contemporaneous with the rising tide of Islam from the seventh through the ninth centuries, not only in the Middle East, where it originated, but also westward from the Levant across the Mediterranean and into the Iberian peninsula in Europe. That process was more or less contemporaneous with the historical rule of Charlemagne, and this lends verisimilitude to the poetical text. The narrative plot has the deceitful king of Sarraguce, Spain (Marsila), aided by a traitorous member of Charlemagne's court (Ganelon), sending word that he will convert to Christianity and become Charlemagne's vassal. Ganelon explains Marsila's plan:
He'll follow you to France, to your Empire,
He will accept the laws you hold and fear;
Joining his hands, will do you homage there,
Kingdom of Spain will hold as you declare (SR 694-97).
In fact, Marsila is "Mahumet's man, he invokes Apollin's aid" (SR 7), which makes him a pagan-Muslim (and whereby the poem paints an entirely improbable picture of Islam). He plans to lure Charlemagne's forces into the field and ambush them. Part of the plan is to ambush and kill ...