Alexander VI, wounded by Ferdinand's treatment of himself, accepted Ludovico Sforza's proposition, and an Act of Confederation was signed on the 22nd of April, 1493, by which the new allies pledged themselves to set on foot for the maintenance of the public peace an army of 20,000 horse and 6,000 infantry.
Ferdinand was frightened when he beheld the formation of this league; but he thought he could neutralise its effects by depriving Ludovico Sforza of his regency, which he had already kept beyond the proper time, though as yet he was not strictly an usurper.

Although the young Galeazzo, his nephew, had reached the age of two-and-twenty, Ludovico Sforza none the less continued regent.

Now Ferdinand definitely proposed to the Duke of Milan that he should resign the sovereign power into the hands of his nephew, on pain of being declared an usurper.
This was a bold stroke; but there was a risk of inciting Ludovico Sforza to start one of those political plots that he was so familiar with, never recoiling from any situation, however dangerous it might be.

This was exactly what happened: Sforza, uneasy about his duchy, resolved to threaten Ferdinand's kingdom.
Nothing could be easier: he knew the warlike nations of Charles VIII, and the pretensions of the house of France to the kingdom of Naples.
He sent two ambassadors to invite the young king to claim the rights of Anjou usurped by Aragon; and with a view to reconciling Charles to so distant and hazardous an expedition, offered him a free and friendly passage through his own States.
Such a proposition was welcome to Charles VIII, as we might suppose from our knowledge of his character; a magnificent prospect was opened to him as by an enchanter: what Ludovica Sforza was offering him was virtually the command of the Mediterranean, the protectorship of the whole of Italy; it was an open road, through Naples and Venice, that well might lead to the conquest of Turkey or the Holy Land, if he ever had the fancy to avenge the disasters of Nicapolis and Mansourah.

So the proposition was accepted, and a secret alliance was signed, with Count Charles di Belgiojasa and the Count of Cajazza acting for Ludovica Sforza, and the Bishop of St.Malo and Seneschal de Beaucaire far Charles VIII.