Saum first presented his son at the court of Minuchihr, and then took him home to Zaboulistan, where he was carefully instructed in every art and science.
At one time, while his father was invading a neighboring province, Zal travelled over the kingdom and stopped at the court of Mihrab, a tributary of Saum, who ruled at Kabul. Though a descendant of the serpent king, Mihrab was good, just, and wise, and he received the young warrior with hospitality. Zal had not been long in Kabul before he heard of the beauties of Rudabeh, the daughter of Mihrab, and she, in turn, of the great exploits of Zal. By an artifice of the princess they met and vowed to love one another forever, though they knew their love would meet with opposition. Saum and Zal both pleaded Zal's cause before Minuchihr, who relented when he heard from the astrologers that a good and mighty warrior would come of the union. Rudabeh's mother won the consent of Mihrab, so that the young people were soon married with great pomp. To them a son was born named Rustem, who, when one day old, was as large as a year-old child. When three years old he could ride a horse, and at eight years was as powerful as any hero of the time.
Nauder succeeded the good Minuchihr, and under him Persia was defeated by the Turanians, and Afrasiyab occupied the Persian throne. But Zal, whose father, Saum, had died, overthrew him and placed Zew upon the throne. Zew's reign was short, and Garshasp, his son, succeeded him. When he was threatened by the Turanians, his people went for aid to Zal, who, because he was growing old, referred them to Rustem, yet of tender age. Rustem responded gladly, and his father commanded that all the horses from Zaboulistan to Kabul be brought forth that his son might select a steed therefrom. Every horse bent beneath his grasp until he came to the colt Rakush, which responded to Rustem's voice, and suffered him to mount it. From that day to his death, this steed was his faithful companion and preserver.
Garshasp was too weak to rule over the kingdom, and Zal despatched Rustem to Mt. Alberz, where he had been told in a dream a youth dwelt called Kai-Kobad, descended from Feridoun. Kai-Kobad welcomed Rustem, and the two, with the noblest of the kingdom, defeated the power of Turan.
After a reign of a hundred years, the wise Kai-Kobad died, and was succeeded by his son, the foolish Kai-Kaus, who, not satisfied with the wealth and extent of his kingdom, determined to conquer the kingdom of Mazinderan, ruled by the Deevs. Zal's remonstrances were of no avail: the headstrong Kai-Kaus marched into Mazinderan, and, together with his whole army, was conquered, imprisoned, and blinded by the power of the White Deev.
When the news of the monarch's misfortune came to Iran, Rustem immediately saddled Rakush, and, choosing the shortest and most peril-beset route, set forth, unaccompanied, for Mazinderan. If he survived the dangers that lurked by the way, he would reach Mazinderan in seven days.
While sleeping in a forest, after his first day's journey, he was saved from a fierce lion by Rakush, who stood at his head.
On the second day, just as he believed himself perishing of thirst, he was saved by a sheep that he followed to a fountain of water; on the third night, Rakush, whom he had angrily forbidden to attack any animal without waking him, twice warned him of the approach of a dragon. The first time the dragon disappeared when Rustem awoke, and he spoke severely to his faithful horse. The second time he slew the dragon, and morning having dawned, proceeded through a desert, where he was offered food and wine by a sorceress. Not recognizing her, and grateful for the food, he offered her a cup of wine in the name of God, and she was immediately converted into a black fiend, whom he slew.
He was next opposed by Aulad, whom he defeated, and promised to make ruler of Mazinderan if he would guide him to the caves of the White Deev. A stony desert and a wide stream lay between him and the demon; but the undaunted Rustem passed over them, and choosing the middle of the day, at which time Aulad told him the Deevs slept, he slew the guards, entered the cavern, and after a terrible struggle, overcame and slew the great Deev.
He then released Kai-Kaus and his army, and restored their sight by touching their eyes with the blood from the Deev's heart.