The aged emperor himself finally engages in a duel with the emir, in the midst of which he is about to succumb, when an angel bids him strike one more blow, promising he shall triumph.
Thus stimulated, Charlemagne slays the emir, and the Saracens, seeing their leader slain, flee, closely pursued by the Frenchmen, who enter Saragossa in their wake.

There, after killing all the men, they pillage the town.
On discovering that Marsile has meantime died of his wound, Charlemagne orders his widow to France, where he proposes to convert her through the power of love.

The remainder of the pagans are compelled to receive baptism, and, when Charlemagne again wends his way through the Pyrenees, all Spain bows beneath his sceptre.
At Bordeaux, Charlemagne deposits upon the altar of St.Severin, Roland's Olifant, filled with gold pieces, before personally escorting the three august corpses to Blaye, where he sees them interred, ere he hurries on to Aix-la-Chapelle to judge Ganelon.
_The Chastisement of Ganelon._ On arriving in his palace, Charlemagne is confronted by Alda or Aude, a sister of Oliver, who frantically questions: "Where is Roland who has sworn to take me to wife ?" Weeping bitterly, Charlemagne informs her his nephew is no more, adding that she can marry his son, but Aude rejoins that, since her beloved is gone, she no longer wishes to live.

These words uttered, she falls lifeless at the emperor's feet.[11] From Spain the emperor made retreat, To Aix in France, his kingly seat; And thither, to his halls, there came, Alda, the fair-and gentle dame.
"Where is my Roland, sire," she cried, "Who vowed to take me for his bride ?" O'er Karl the flood of sorrow swept; He tore his beard, and loudly wept.
"Dear sister, gentle friend," he said, "Thou seekest one who lieth dead: I plight to thee my son instead,-- Louis, who lord of my realm shall be." "Strange," she said, "seems this to me.
God and His angels forbid that I Should live on earth if Roland die." Pale grew her cheek--she sank amain, Down at the feet of Carlemaine.
So died she.

God receive her soul! The Franks bewail her in grief and dole.
The time having come for the trial, Ganelon appears before his judges, laden with chains and tied to a stake as if he were a wild beast.