During the ‘Great Interregnum’[35] Alfonso was one of the claimants for the imperial crown, but had neither money nor sufficient popularity to carry through this foolish project, for which he heavily overtaxed his people. He also planned an invasion of Africa in grand crusading style, but had to turn his attention instead to struggling against unruly sons. He died with little accomplished save his reputation for wisdom. The reign of Alfonso X was a prelude to a century and a half of anarchy in Castile, a period when few of her kings could claim to be either ‘wise’ or ‘learned’, and when four of them by ill fortune ascended the throne in childhood, and so presented their nobles with extra opportunities for seeking their own ambitions at the royal expense. On one struggle during this century and a half we have already touched--the bitter feud between Pedro ‘the Cruel’, the Nero of Spain, and his half-brother, Henry of Trastamara.[36] There is no end to the list of crimes of which this monster has been accused, from strangling his rival’s mother, and calmly watching while his half-brother, a twin of Henry of Trastamara, was pursued and cut down unarmed by the royal guard, to ordering that the young bride with whom he had refused to live should be given poisonous herbs that she might die. Stained, indeed, must the Black Prince have felt his honour when he discovered what a brother-in-arms he had crossed the Pyrenees to aid--one who would massacre prisoners for sheer love of butchery, burn a priest for prophesying his death, and murder an archbishop in a fit of savagery. It is probably true to describe this worst of the Spanish kings as mad: many of his atrocities were so meaningless, such obvious steps to his own downfall, because they alienated those who tried to remain loyal to his cause. His end, when it came, rejoiced the popular heart and imagination, for Pedro, according to tradition, was at last entrapped by the crafty Du Guesclin, lately released from imprisonment by the Black Prince, and once more in the service of Henry of Trastamara.