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.
Charlemagne's dreams in laisses 56 and 57 are, once deciphered, accurate forecasts of events to come. After all, his dreams are "sent by angels"; their reliability is part of the package of benefits Charlemagne receives as a holy Christian monarch (67.836). His dreams are easy to decode; the first shows how a trusty weapon of his—Roland—will be destroyed by Ganelon's rage. In the second, "a vicious boar is biting his right arm" (57.727) and Ganelon had earlier, talking to Marsilla, compared Roland to Charlemagne's right arm: "If someone were to cause the death of Roland, / then Charles would lose the right arm from his body" (45.596-597). The poet of The Song of Roland, as we mentioned earlier, does not often use simile; there is, however, plenty of metaphor, as we see here.
In laisse 58, in which Ganelon nominates Roland for the rear guard ("My stepson Roland...You have no lord of such great vassalage," says Ganelon, 58.743- 744), we see again the mirror-play of the poem at work. The scene echoes the scene in laisse 20, in which Roland nominates Ganelon for the envoy "Ganelon, my stepsire, is your man," says Roland (20.277). Charlemagne, thanks to his prophetic dreams, knows that Roland is doomed and that Ganelon is to blame; he grieves and worries over this, and tries to give Roland extra troops to protect him against the danger he foresees (Roland's over-proud refusal to accept help in this instance foreshadows his later refusal to blow the oliphant), but he does nothing definite to stop the sequence of events that will end in the massacre at Roncesvals. Perhaps he is not altogether sure about the reliability of his dream-visions; perhaps he feels that such sleeping prophecies, unsubstantiated, are not proper grounds for strategic decisions. Perhaps the problem that confronts Charlemagne is something like the problem of human free will as it confronts God; although, by heavenly favor and his unquestioned command over his men, Charlemagne is, within the limited sphere of the Frankish army, almost omniscient and omnipotent. And yet he surely intervenes less than he might to avert the tragedy of Roncesvals; perhaps he has something like the Christian God's concern for human freedom of conscience to the same degree that he has superhuman, almost godlike stature among the Franks.
In the pagans' assembly of their army for the ambush, the symmetry between the Christians and the Muslims is again clear. Marsilla's nephew is as bold and brash as Charlemagne's nephew; the pagans attribute to the glove the same ceremonial meaning as do the Christians; twelve Saracen peers are chosen to combat the twelve Frankish peers. The way in which the Muslims trust in the righteousness of their religion to ensure success on the battlefield is similar to the attitude of Charlemagne's men, only, of course, reversed: "Mohammed's worth far more than Rome's Saint Peter— / serve him, and honors of the field are ours," proclaims a pagan count (74.921-922).