The following document shows that Francesco Sforza realised how much he owed to Cosimo de’ Medici. When on the death of Filippo Maria Visconti in 1447 Milan declared herself a Republic, popular feeling in Florence ran high in her favour. It needed all Cosimo’s authority and influence to induce his fellow-citizens to assist Sforza in seizing supreme power. Cosimo saw that as a republic Milan would inevitably fall a prey to Venice, and thus the communications of Italy with the North would be cut off. A strong ruler who owed his crown to Florence would be an invaluable ally, and preserve the balance of power in Italy. We shall see that Piero faithfully carried out his father’s policy. Francesco Sforza, _Duke of Milan_, _&c._ _&c._ As we have always felt a particular affection for the magnificent Cosimo de’ Medici of Florence on account of his singular virtues, and as he also has loved us and all that pertains to us, we are bound and obliged to love all that belongs to him. Now here in Milan Pigello Portinaro, a Florentine citizen and merchant, the administrator and partner in the business and bank of the Magnificent Cosimo de’ Medici and of Piero and Johanni his sons in Milan, who has served us and the illustrious Madonna Bianca our consort ever since he came to inhabit this our city, about eleven years ago, with very large sums of money, with stuffs and with jewels, and with loans of divers kinds as appear by the entries in our private books. These services, subsidies, and favours given by the said Pigello according to the orders of the aforesaid Magnificent Cosimo and his sons were most pleasing and acceptable to us because they were given willingly, and the said Pigello carried them out and fulfilled them with great diligence, loyalty, and love towards us, and with admirable discretion, by which means we were enabled to arrange our affairs. Pigello made every effort to do this with the smallest possible loss to us, and we are sure he will continue to do so. Therefore we are much pleased and have been well served by the aforesaid Pigello; and all the profit, lucre, and gain that the said Pigello has made, either in their name or in his own with us and with our stewards, officials, and any other agents of ours, we for the above-named reasons approve of and are well content. By this our letter we declare that they can have and hold all without fear of contradiction or qualms of conscience, releasing and absolving the said Magnificent Cosimo, his sons and the said Pigello, and their sons and heirs in perpetuity from any claims; promising for ourselves, our sons and successors, that no question shall be raised about any profits or gains they may have made with us up to the present day for the above said reasons, or for any depending or arising therefrom. Because as has been said we have already, and by this our letter we do now make a general donation of the aforesaid