The latter departed for Toledo, whence he was soon recalled, however, for his monarch could do nothing without him.

Thus restored to favor, the Cid began the siege of Zamora, which lasted so long that the inhabitants began to suffer all the pangs of famine.
At last a Zamoran by the name of Vellido (Bellido) Dolfos came out of the town in secret, and, under pretense of betraying the city into Don Sancho's hands, obtained a private interview with him.

Dolfos availed himself of this opportunity to murder the king, and rushed back to the city before the crime was discovered.

He entered the gates just in time to escape from the Cid, who had mounted hastily, without spurs, and thus could not urge Babieca on to his utmost speed and overtake the murderer.
"'Cursed be the wretch! and cursed He who mounteth without spur! Had I arm'd my heels with rowels, I had slain the treacherous cur.'" _Ancient Spanish Ballads_ (Lockhart's tr.).
The grief in the camp at the violent death of the king was very great.

Don Diego Ordonez immediately sent a challenge to Don Arias Gonzalo, who, while accepting the combat for his son, swore that none of the Zamorans knew of the dastardly deed, which Dolfos alone had planned.
"'Fire consume us, Count Gonzalo, If in this we guilty be! None of us within Zamora Of this deed had privity.
"'Dolfos only is the traitor; None but he the king did slay.
Thou canst safely go to battle, God will be thy shield and stay.'" _Ancient Spanish Ballads_ (Lockhart's tr.).
This oath was confirmed by the outcome of the duel, and none of the besiegers ever again ventured to doubt the honor of the Zamorans.
[Sidenote: Alfonso king.] As Don Sancho had left no children to inherit his kingdom, it came by right of inheritance to Don Alfonso, who was still at Toledo, a nominal guest, but in reality a prisoner.