The onset of Alfonso at the head of the Christian cavalry was so fierce that the ranks of the Almoravides were thrown into confusion; not less successful was Sancho, King of Navarre, against the Andalusians, who retreated toward Badajoz. But the troops of Seville kept the field, and fought with desperate valor: they would, however, have given way, had not Yussef at this critical moment advanced with his reserve and his own guard, consisting of his bravest troops, and assailed the Christians in the rear and flanks. This unexpected movement decided the fortune of the day. Alfonso was severely wounded and compelled to retreat, but not until nightfall, nor until he had displayed a valor worthy of the greatest heroes. Though his own loss was severe, amounting, according to the Arabians, to twenty-four thousand men, that of the enemy could scarcely be inferior, when we consider that this victory had no result; Yussef was evidently too much weakened to profit by it. Not long after the battle, Yussef being called to Africa by the death of a son, the command of the Almoravides devolved on Syr ben Abu-Bekr, the ablest of his generals. That general advanced northward, and seized some insignificant fortresses; but the advantage was but temporary, and was more than counterbalanced by the disasters of the following year. The King of Saragossa, Abu-Giafar, had hoped that the defeat of Zalaca would prevent the Christians from attacking him; but that of his allies, the Mahometan princes, in the neighborhood, and the taking of Huesca by the King of Navarre, convinced him how fallacious was his fancied security. Seeing that no advantage whatever had accrued from his former expedition, Yussef now proclaimed the Alhiged, or holy war, and invited all the Andalusian princes to join him. In A.D. 1088, he again disembarked at Algeziras and joined the confederates. But this present demonstration of force proved as useless as the preceding: it ended in nothing; owing partly to the dissensions of Mahometans, and partly to the activity of the Christians, who not only rendered abortive the measures of the enemy, but gained some signal advantages over them. Yussef was forced to retreat on Almeida. Whether through the distrust of the Mahometan princes, who appear to have penetrated his intention of subjecting them to his empire, or through his apprehension of Alfonso, he again returned to Africa, to procure new and more considerable levies. In A.D. 1091 he landed a third time at Algeziras, not so much with the view of humbling the Christian King as of executing the perfidious design he had so long harbored. For form's sake, indeed, he invested Toledo, but he could have entertained no expectation of reducing it; and when he perceived that the Andalusian princes refused to join him, he eagerly left that city, and proceeded to secure far dearer and easier interests: he openly threw off the mask, and commenced his career of spoliation.