Answer:
Readers associate certain thoughts and feelings with certain places (such as graveyards, old houses, and churches).
I think it is called Irony... not entirely sure...
Ganelon, who was Roland's stepfather, got angry to Roland because of his boastfulness. He got jealous of him due to his success in the battlefield and popularity among the Franks. He got even angrier when Roland nominated him into a suicidal mission as messenger to the Saracens (Muslim Arabs). With this, he got offended and vowed vengeance.