Alfonso XI showed the lack of parental guidance during youth by the errors of his early manhood, among other indiscretions forming an illegitimate alliance with a lady who became the mother of Don Enrique of Trastamara, who later slew his half–brother Pedro “the Cruel.” By the great victory of the Rio Salado, in 1340, Alfonso retrieved his damaged reputation in the eyes of the people and firmly established the kingdom upon an impregnable basis. The combined hosts of Spanish Moors and Africans had assembled and laid siege to Tarifa, the southernmost town in Spain. The Christian armies, under the lead of Alfonso and the king of Portugal, met and overthrew them near the plains of Algeciras, inflicting such slaughter that the dead lay piled in heaps, the slain, it was estimated, amounting to two hundred thousand. This was the last invasion from Africa, which had been so prolific in barbarian and semi–barbarian conquerors; and if any other was in contemplation it was prevented the following year, when Alfonso’s fleet destroyed that of the Moors in the Straits of Gibraltar. King Alfonso besieged the fortress of Gibraltar itself—which had been in Moorish possession since 1333—but failed to dislodge the enemy, and it was not until more than a hundred years later, in 1462, that it again fell into the hands of the Spaniards. Alfonso doubtless held the ambitious project of ridding the peninsula entirely of the Moors; but his country was not sufficiently united, and one hundred and fifty years were to elapse before the consummation of this object, under King Ferdinand and Queen Isabella. That he was a valiant warrior, despite his many failings, is shown by his death in the field, while besieging Gibraltar, when he fell a victim to the terrible pestilence known as the “black death,” in the year 1350.