When the line of Eranshahr broke upon the bloody sands of Qadisiyyah and General Rostam Farrokhzad fell, King Yazdegerd III summoned his veteran scribe to lay bare the agony of his heart. Preparing to make his way toward Merv, the eastern stronghold governed by the border-lord Mahuy Suri, the monarch composed an epistle infused with bitter sorrow, fury, and longing. The letter opened with magnificent praise for the Almighty Creator—the Lord of wise counsel who commands the wandering orbit of red Mars and the radiant Sun, the Sovereign over both the mighty elephant and the lowly ant, He who brings creation out of nothingness by sole divine decree without need of any counselor.
Then the King gave voice to his despair: the luster and majestic splendor of the ancient Sasanian realm had faded. He mourned the terrible loss of Rostam Farrokhzad, cut down on the battlefield by Saad ibn Abi Waqqas, whom the King characterized as an obscure adversary lacking lineage, wisdom, or noble stature. With Ctesiphon now occupied by the advancing host and the speckled raven of misfortune brooding over the realm, Yazdegerd commanded Mahuy Suri to mobilize all the forces of the East, inspiring the warriors to unite for a great stand. Promising to ride like the wind following the messenger to join him in Merv, the King selected a sage and perceptive envoy to carry this fateful decree.