The road from granite-walled Avila to the south is across a wild and desolate waste, frowned down upon on either hand by the savage crests of the grim sierras of the Guadarrama. It winds along gorges and ravines and rocky river-beds, and has always been, even in the days of Spanish power and glory, about as untamed and savagely picturesque a road as one could well imagine. Along this hard and desolate road, only a few days after their determination had been reached, to start upon a crusade the brother and sister plodded. Theresa carried her crucifix, and Pedro his toy sword, while in a little wallet at his side were a few bits of food taken from the home larder. This stock of food had, of course, been taken without the knowledge of the mother, who knew nothing of their crusade, and this, therefore, furnished for Theresa another sin, for which she must do penance, and another reason for the desired martyrdom. They had really only proceeded a few miles into the mountains beyond Avila, but already their sturdy little legs were tired, and their stout little backs were sore. Pedro thought crusading not such very great fun after all; he was always hungry and thirsty, and Theresa would only let him take a bite once in a while. “Don’t you suppose there is a Moorish castle somewhere around here that we could capture, and so get plenty to eat?” he inquired of his sister. “That is what the Cid was always finding. Don’t you remember how nicely he got into Alcacer and slew eleven Infidel knights, and found ever so much gold and things to eat? This is what he said, you know: “‘On, on, my knights, and smite the foe! And falter not, I pray; For by the grace of God, I trow, The town is ours this day!’” “O Pedro, dear, why will you think so much of things to eat,” groaned Theresa. “Do you not know that to be hungry is one way to be a martyr. And besides, it is, I doubt not, our just punishment for having taken any thing to eat without letting mother know. We must suffer and be strong, little brother.” “That’s just like a girl,” cried Pedro, a trifle scornfully. “How can we be strong if we suffer? I can’t, I know.” But before Theresa could enter upon an explanation of this most difficult problem--one that has troubled many older heads than little Pedro’s,--both the children started in surprise, and then involuntarily shrunk closer to the dark gray rock in whose shadow they were resting. For there, not a hundred yards distant, coming around a turn in the road, was one of the very Infidels they had come out to meet and conquer, or be martyred by.