Cuevas de Ayllon © Mark Wade

Now the history relates that King Don Ferrando contended with King Don Ramiro of Aragon for the city of Calahorra, which each claimed as his own; in such guise that the King of Aragon placed it upon the trial by combat, confiding in the prowess of Don Martin Gonzalez, who was at that time held to be the best knight in all Spain.

King Don Ferrando accepted the challenge, and said that Rodrigo of Bivar should do battle on his part, but that he was not then present.

And they plighted homage on both parts to meet and bring each his knight, and the knight who conquered should win Calahorra for his Lord.

Having ratified this engagement, they returned into their own lands.

And immediately Ferrando sent for Rodrigo of Bivar, and told him all the matter as it then stood, and that he was to do battle.

Well pleased was Rodrigo when he heard this, and he accorded to all that the King had said that he should do battle for him upon that cause; but till the day arrived he must needs, he said, go to Compostella, because he had vowed a pilgrimage; and the King was content therewith, and gave him great gifts.