King Khosrow Anushirvan journeyed from Gorgan toward Sari and Amol at the season when nightingales filled the verdant air with song. The plains and hills stretched as an unbroken wilderness of emerald beauty, yet the King's heart was heavy with deep reflection. Ascending a lofty peak upon his swift bay steed, he gazed out across the blossoming fields, the pristine streams, and the abundant game. In reverence, the Shah bowed his head in prayer to the Almighty Creator—the Fashioner of the sun and moon, the Opener of all paths—recalling how King Fereydun, the God-fearing monarch of ancient memory, had once chosen these lush woods as his seat.
As Khosrow paused in contemplation, a spokesman for the local inhabitants approached the throne, pouring out the sorrow of the borderlands. He revealed that despite the celestial paradise of their surroundings, their lives were consumed by terror; nomadic Turkic invaders routinely swept through these mountain passes, pillaging towns, slaughtering families, and carrying off livestock, leaving neither man nor beast unmolested. This very corridor remained the open gateway through which foreign hosts struck into the heartland of Iran. The elder implored the Sovereign to use his imperial wisdom to seal this breach forever.
Upon hearing the suppliant's anguish, tears filled Khosrow's eyes. Turning to his chief minister, the monarch declared that a true ruler cannot feast in comfort or wear the royal crown with honor while the noble farmers and subjects suffer under tyranny. To leave such fertile valleys to be laid waste would strip all renown and divine glory from the throne of Iran.
Without delay, Khosrow issued royal decrees to summon the most renowned master builders, masons, and engineers from Rome, India, and every realm of the empire. He threw open the royal treasuries, commanding that all labor be generously compensated so that no peasant or landowner should endure hardship or forced toil. Under the supervision of a wise Mobad, a monumental wall was raised from the depths of the waters up to the sky, forged of solid stone and mortar, ten ropes in height. Upon this impregnable barrier, a colossal iron gate was set, forever shielding the flock of Iran from the ravenous wolves of war. Placing vigilant garrisons along the entire frontier, Khosrow led his victorious host back, confident that the realm was at last secure.