Ludovico deserves the doubtful credit of having been the first to bring his goods to market. French ambition had two excuses for intervention in Italy. The first was the claim of Orleans to Milan, resting on the marriage of Valentina Visconti to the first Duke of Orleans, and on the marriage contract of Valentina, confirmed by Clement VII, in which her right to succeed to her father in default of male heirs was recognised. There seems also to have been a will of Gian Galeazzo Visconti, securing the succession to her male issue in default of the direct male line; but Ludovico alone knew of this and caused all known copies to be destroyed. Legal objections might be urged against all these grounds of claim, but they were good enough to support a dynastic war. Louis of Orleans had in 1491 recovered his favour at Court, and it was not impossible that Milan would be made the object of the French attack. Milan lay dangerously near to France, and strategically was much less difficult of access than Naples. On the other hand Charles might well be unwilling to aggrandise one of the most powerful of his nobles, a possible heir to the throne, who, though reconciled, had not long ago been in arms against his King. It was Ludovico's natural policy to endeavour to divert this danger from himself.
The second French pretext was the claim to Naples, resting on similar grounds, and similarly open to cavil. Joanna I, Queen of Naples of the first Angevin line, had no heirs of her body. The lawful heir was Charles of Durazzo, descended from the younger son of Charles II of Naples. Being at enmity with Charles of Durazzo, Joanna adopted her remote cousin Louis, Duke of Anjou by the second creation. Charles and his descendants had successfully defended their rights against Louis and his heirs, until their line also died out in Joanna II. The latter, in order to defend herself against the attacks of Louis III of Anjou, adopted Alfonso of Aragon as her heir. When later Alfonso wished to make himself master of Naples without waiting for Joanna's death, Joanna revoked this act of adoption, adopted Louis III, and on her death (1435) made his brother Rene her heir. Thus Alfonso, who seized the kingdom, was legally only a successful usurper; and all the claims which Louis I derived from the adoption of Joanna I, together with the claims of the house of Durazzo, were united in the person of Rene, who more than once tried to recover his heritage. The rights of Rene passed in 1481, through his nephew the Count of Maine, by will and also, though not so certainly, by succession, to Louis XI, and after him to Charles VIII. Sixtus IV, although he refused to consider the application of Charles du Maine for the investiture of Naples, in 1482, moved by different thoughts, urged Louis to undertake the conquest of the kingdom, "which belongs to him." At the beginning of the reign of Charles VIII there was some talk of putting forward Rene of Lorraine, a descendant through the female line of the house of Anjou, as claimant to the kingdom, but these proposals seem never