Afrasiab's Riders Plunge into the Trench

From C4.29, Afrasiab’s Night Attack Fails. It illustrates C4.29.21–28:

C4.29.21
But near the royal tent, across the ground,The karnays then suddenly began to sound.
C4.29.22
Saddle tabiras thundered through the black;The sable banner rose for the attack.
C4.29.23
The foremost riders spurred their steeds and cried,And drove their horses toward the trench’s side.
C4.29.24
But many riders plunged into the fosse,While others wheeled away in fear of loss.
C4.29.25
Then Rostam thundered upward from the plain,And darkened heaven with his riders’ train.
C4.29.26
Giv, Gudarz, Tus came from the other side;Ahead, tabiras, karnays thundered wide.
C4.29.27
The Shah with Kaveh’s banner joined the fight;The air turned violet with the swords’ bright light.
C4.29.28
The horses faltered and the riders reeled;“Take! Bind! Strike! Kill!” rang out across the field.