A. H. Johnson, Europe in the Sixteenth Century…
“ At the close of the Neapolitan war, the alliance between the houses of Hapsburg and Spain, based on the marriage of the Archduke Philip, son of Maximilian, with Joanna, the daughter of Ferdinand of Aragon and Isabella of Castile, threatened to break up. By the deaths in 1497, and 1500, of John, the eldest son, and of Michael of Portugal, the grandson of the Spanish monarchs, Joanna became the heiress of Castile and Aragon,21 and, in the event of Isabella’s death, would become Queen of Castile to the exclusion of her father. ”
