Ganelon soon arrives back at the Frankish camp and tells the emperor and his men that his embassy was a triumph. He shows them the treasure and the hostages and says that Marsilla will arrive in Charlemagne's capital, Aix, no more than a month after their own arrival to become a Christian. Charlemagne and his men are most pleased, looking forward to their return to sweet France, for which they have longed for years.
But then, when he goes to sleep that night, Charlemagne has vivid and strange dreams prophecying the doom that will soon meet the Franks. In one of these sleeping visions, Ganelon plays the villain's part. The next morning, the Franks must decide who will go in the rear guard and who in the van. Ganelon, of course, suggests Roland as the most suitable leader possible for the rear guard. Roland does not protest, but instead proudly accepts the office. He is, however, very irritated; he knows perfectly well that Ganelon did not suggest him for the rear guard out of the kindness of his heart, though he does not suspect his stepfather of anything approaching his actual plot—and snidely insults his stepfather. The emperor, watching all this, is filled with foreboding and, trying to protect his valiant nephew, urges him to take half of all his army. Roland, with his usual fine and proud spirit, will have nothing to do with the offer; he had no dreams of doom and wants to take the usual number for the guard.
Roland begins to organize his guard, choosing eleven of the best men to ride with him, including his closest companion, Olivier, and the ferocious archbishop, Turpin, along with twenty thousand knights. He picks Gautier to lead a band of men to scout the hillsides and ravines along the pass.
As the main body of the Frankish army cross over into their homeland, Charlemagne weeps among the general rejoicing and confesses his fears and visions to Naimes.
Meanwhile, Marsilla's nephew Aelroth is putting together the army that will ambush the Frankish rear guard, choosing eleven comrades from among the finest Saracen warriors, including Marsilla's brother Falsaron, the evil magician Corsablis, and Margariz, who makes all the ladies of Seville swoon. They then round up a hundred thousand Saracen warriors to lead in this glorious expedition of slaughter.
As we saw earlier, the temporal arrangement of The Song of Roland, as far as the order in which the poet puts the events he narrates goes, is remarkably simple. However, the poet does refer to events he has not yet recounted by foreshadowing and omens and, sometimes, direct statements ("Today the Frenchmen are to know great pain," (66.816)). This somewhat complicates the generally straightforward temporality of the poem.