While Don Sancho and his invaluable ally were thus engaged, Don Garcia, King of Galicia, who was also anxious to increase his kingdom, deprived his sister Dona Urraca of her city of Zamora.  In her distress the infanta came to Don Sancho and made her lament, thereby affording him the long-sought pretext to wage war against his brother, and rob him of his kingdom.

This war, in which the Cid reluctantly joined, threatened at one time to have serious consequences for Sancho.  He even once found himself a prisoner of Garcia’s army, shortly after Garcia had been captured by his.  The Cid, occupied in another part of the field, no sooner heard of this occurrence than he hastened to the Galician nobles to offer an exchange of prisoners; but, as they rejected his offer with contempt, he soon left them in anger.

    “’Hie thee hence, Rodrigo Diaz,
    An thou love thy liberty;
    Lest, with this thy king, we take thee
    Into dire captivity.’”
          Ancient Spanish Ballads (Lockhart’s tr.).

The wrath which the Cid Campeador experienced at this discourteous treatment so increased his usual strength that he soon put the enemy to flight, recovered possession of his king, and not only made Don Garcia a prisoner, but also secured Don Alfonso who had joined in the revolt.  Don Garcia was sent in chains to the castle of Luna, where he eventually died, entreating that he might be buried, with his fetters, in the city of Leon.

[Sidenote:  Alfonso at Toledo.] As for Don Alfonso, Dona Urraca pleaded his cause so successfully that he was allowed to retire into a monastery, whence he soon effected his escape and joined the Moors at Toledo.  There he became the companion and ally of Alimaymon, learned all his secrets, and once, during a pretended nap, overheard the Moor state that even Toledo could be taken by the Christians, provided they had the patience to begin a seven-years’ siege, and to destroy all the harvests so as to reduce the people to starvation.  The information thus accidentally obtained proved invaluable to Alfonso, as will be seen, and enabled him subsequently to drive the Moors out of the city Toledo.

In the mean while Sancho, not satisfied with his triple kingdom, robbed Dona Elvira of Toro, and began to besiege Dona Urraca in Zamora, which he hoped to take also in spite of it almost impregnable position.

    “’See! where on yon cliff Zamora
      Lifteth up her haughty brow;
    Walls of strength on high begird her,
      Duero swift and deep below.’”
          Ancient Spanish Ballads (Lockhart’s tr.).

The king, utterly regardless of the Cid’s openly expressed opinion that it was unworthy of a knight to attempt to deprive a woman of her inheritance, now bade him carry a message to Dona Urraca, summoning her to surrender at once.  The hero went reluctantly, but only to be bitterly reproached by Urraca.  She dismissed him after consulting her assembled people, who vowed to die ere they would surrender.