The immediate heir to the throne was Isabella’s elder half-brother Henry.  Her mother was the Princess of Portugal, so that on both sides she was descended from John of Gaunt, the father of our Lancastrian line.  Both her childhood and that of Ferdinand of Aragon, a year her junior, were passed amidst tumultuous scenes of civil war.  Henry, good-natured, incompetent, and debauched, yielded himself to favourites, hence he was more than once almost rejected from his throne.  Old King John II. of Aragon was similarly engaged in a long civil war, mainly owing to his tyrannous treatment of his eldest son, Carlos.

But by 1468 Isabella and Ferdinand were respectively recognised as the heirs of Castile and Aragon.  In spite of her brother, Isabella made contract of marriage with the heir of Aragon, the instrument securing her own sovereign rights in Castile, though Henry thereupon nominated another successor in her place.  The marriage was effected under romantic conditions in October 1469, one circumstance being that the bull of dispensation permitting the union of cousins within the forbidden degrees was a forgery, though the fact was unknown at the time to Isabella.  The reason of the forgery was the hostility of the then pope; a dispensation was afterwards obtained from Sixtus IV.  The death of Henry, in December 1474, placed Isabella and Ferdinand on the throne of Castile.

II.—­Overthrow of the Moorish Dominion

Isabella’s claim to Castile rested on her recognition by the Cortes; the rival claimant was a daughter of the deceased king, or at any rate, of his wife, a Portuguese princess.  Alfonso of Portugal supported his niece Joanna’s claim.  In March 1476 Ferdinand won the decisive victory of Toro; but the war of the succession was not definitely terminated by treaty till 1479, some months after Ferdinand had succeeded John on the throne of Aragon.

Isabella was already engaged in reorganising the administration of Castile; first, in respect of justice, and codification of the law; secondly, by depressing the nobles.  A sort of military police, known as the hermandad, was established.  These reforms were carried out with excellent effect; instead of birth, merit became the primary qualification for honourable offices.  Papal usurpations on ecclesiastical rights were resisted, trade was regulated, and the standard of coinage restored.  The whole result was to strengthen the crown in a consolidated constitution.

Restrained by her natural benevolence and magnanimity, urged forward by her strong piety and the influence of the Dominican Torquemada, Isabella assented to the introduction of the Inquisition—­aimed primarily at the Jews—­with its corollary of the Auto da fe, of which the actual meaning is “Act of Faith.”  Probably 10,220 persons were burnt at the stake during the eighteen years of Torquemada’s ministry.

Now, however, we come to the great war for the ejection of the Moorish rule in southern Spain.  The Saracen power of Granada was magnificent; the population was industrious, sober, and had far exceeded the Christian powers in culture, in research, and in scientific and philosophical inquiry.