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. This at once aroused the jealousy of Ferdinand against her husband the archduke. The temporary division of Castile and Aragon would arrest the unification of the Peninsula; while the prospect of Spain eventually falling to the Hapsburg was equally distasteful to him. | Treaty of Lyons, April 5, 1503; and of Blois, Sept. | 22, 1504. Ferdinand had accordingly rejected the treaty of Lyons (April 1503), concluded between Philip and Louis XII. for the settlement of the Neapolitan quarrel. By that treaty, it had been agreed that the kingdom of Naples should one day fall to Claude, the infant daughter of Louis XII., who had already, in 1501, been betrothed to Charles, the young son of the archduke. Philip, abandoned by his father-in-law, clung all the closer to the French alliance, and was supported by his father, Maximilian, who hoped by this marriage treaty to realise his most magnificent dreams. In September 1504, at Blois, Louis XII., influenced by his wife, Anne of Brittany, promised Milan, Genoa, Asti, Brittany, and Blois, as Claude’s dower, to which Burgundy was to be added in the event of his own death without male heirs. In the following year, Maximilian actually proposed, with the approval of the French Queen, that the Salic Law should be repealed, in order that Claude might succeed her father on the French throne. | Second Treaty of Blois. Oct. 12, 1505.