With the aid of his "Slavs," the Sultan not only banished brigandage and rebellion from Spain, but waged war with the Christians of the north with brilliant success. The Mohammedan realm was menaced by more dangers than those of internal anarchy. It was pressed between two threatening and warlike kingdoms, each of which required to be kept in watchful check. To the south the newly-founded empire of the Fātimite Khalifs in North Africa was a standing menace. It was natural that the rulers of the Barbary coast should remember that the Arabs before them had used Africa as a stepping stone to Spain; the traditional policy of the African dynasties was to compass, if possible, the annexation of the fair provinces of Andalusia. It was only by skilfully working upon the sectarian schisms, and consequent insurrections, which divided the Berbers of Africa, that the Sultan succeeded in keeping the Fātimites at a distance. He did succeed, however, so well, that at one time a great part of the Barbary coast paid homage to the ruler of Spain, who also obtained possession of the important fortress of Ceuta. A great part of the Spanish revenue was devoted to building a magnificent fleet, with which Abd-er-Rahmān disputed with the Fātimites the command of the Mediterranean. On the opposite side, on the north, the Moslem power had to deal with an even more threatening enemy. The Christians of the Asturias had sprung from very small beginnings, but they were now increasing in strength, and they had the stimulating thought to spur them on, that they were reconquering their own land. When first they had felt the shock of the Moslem invasion, their rout had been utter and complete. They had fled to the mountains of the Asturias, where their trifling numbers and the inaccessibility of their situation gave them safety from the Mohammedan attack. Pelagius, the "old Pelayo" of the ballad, had but thirty men and ten women with him in the cave of Covadonga, which became the refuge of the Gothic Christians; and the Arabs did not think it worth while to hunt down the little remnant of refugees. Here, in the recesses of the cave, which was approached through a long and narrow mountain pass, and entered by a ladder of ninety steps, a handful of men might have set an army at defiance.