In days of old, upon the desert plains of the spear-wielding Arab horsemen, there ruled a noble and righteous king named Merdas. He was a devout worshipper of God, filled with holy awe, and boundlessly generous to all living creatures. Merdas possessed vast herds of every milk-bearing livestock—milch-cows, ewes, goats, and noble Arabian steeds. He entrusted the milking to pure-hearted damsels, and whenever any soul in the realm stood in need of milk or nourishment, they could freely partake from his overflowing bounty.
Yet this virtuous monarch had a single son who was utterly devoid of human tenderness and love. His name was Zahhak—an ambitious and fearless youth, yet reckless, arrogant, and impure of heart. In the Pahlavi tongue, he was called Bivarasp, for 'Bivar' signifies ten thousand, and he owned ten thousand Arabian chargers adorned with golden bits and bridles. Day and night, he spent two-thirds of his hours in the saddle, driven by immense pride.
One dawn, Iblis, the arch-tempter, appeared before Zahhak in the disguise of a benevolent and wise counselor. Beguiling the prince's heart away from goodness, Iblis demanded a solemn oath of secrecy and obedience before revealing his council. Naive and greedy for glory, Zahhak swore never to divulge the secret nor stray from his advice.
Then Iblis sowed the fatal seed of treason: 'Why should an old man linger upon the throne when he has a glorious son like you? Time tarries too long over your father. Seize his realm and stature; obey me, and I shall make you the sovereign ruler of the world.' At first, Zahhak shuddered at the thought of patricide and refused, declaring such an act improper. But Iblis threatened him with the curse of a broken oath, warning that he would be disgraced forever while his father remained exalted.
Trapped by fear and ambition, Zahhak yielded and asked Iblis how to execute the deed. Merdas had a breathtaking garden within his estate where he was accustomed to rise before dawn, wash his head and body in seclusion, and pray to the Almighty Lord. Perverse Iblis dug a deep pit directly along the king's customary path, concealing the trap with dry twigs and foliage.
When night still shrouded the earth, the pious king stepped into his garden to pray. He plunged into the hidden abyss, his body crushed, and his holy soul departed. Thus perished Merdas—a father who had never let a harsh wind blow upon his son, who had raised him with loving toil and lavished all his treasures upon him. Base and tyrannical Zahhak seized his father's place, placing the crown of the Arabs upon his head and assuming rule over their destinies.