The successor which Kai-Khosrau had chosen proved a just ruler until he became jealous of his own son, Isfendiyar, who was also a great warrior, and who, like Rustem, accomplished seven great works.  He, too, overcame demons, wolves, lions, enchanters, dragons, and unchained elements, and on one occasion proceeded to rescue two of his sisters, who were detained captives in the fortress of Arjasp, a demon king.  Knowing he could not enter this stronghold by force, Isfendiyar penetrated into it in the guise of a merchant, having hidden in his chests a number of soldiers, who were to help him when the right moment came.  Thanks to their aid and to the fact that he began by intoxicating his foe, Isfendiyar triumphed.

The time came, however, when Isfendiyar was ordered by his father to bring Rustem to court in chains.  This task proved most distasteful to the prince, who, on approaching Rustem, explained that he was not a free agent.  Because the old hero obstinately refused to be manacled, the two warriors began fighting, and at the end of the day Rustem and his steed were so severely wounded that Isfendiyar felt sure they would not be able to renew the fight on the morrow.

It happened, however, that the aged Zal, on seeing his wounded son, remembered his partly burned feather, and promptly cast it into the fire.  Immediately the Simurgh appeared, and with one touch of her golden wings healed the horse, and used her clever beak to draw the lance out of Rustem’s side.  Having thus healed her nursling’s son, the Simurgh vanished, leaving Rustem and his steed in such good condition that they were able to renew the battle on the morrow.  This time, Isfendiyar perished beneath Rustem’s blows, exclaiming that the hero was not to blame for his death and that he fell victim to his father’s hate.  In token of forgiveness, he begged Rustem to bring up his son, a wish which was piously carried out by the brave warrior as long as he lived.

Because it had been written in the stars that “he who slew Isfendiyar would die miserably,” Rustem was somewhat prepared for his tragic fate.  It seems his young half-brother finally became so jealous of him that he plotted to kill him by digging seven pits lined with swords and spears.  These were hidden in a road along which Rustem had to travel when he came in the king’s name to claim tribute.  Falling into the first pit, Rustem set his spurs to Rakush’s sides; and the brave steed, although wounded, leaped out of this trap, only to tumble into a second and third.  From pit to pit Rustem and his dauntless horse landed at the bottom of the seventh, fainting from their many wounds.