The king of Naples was his natural enemy, and he had cause to suspect that Piero de Medici might abandon his alliance.
Ser Piero on his part was four times married, and had by his last two wives nine sons and two daughters; but he had from the first acknowledged the boy Leonardo and brought him up in his own house, principally, no doubt, at Florence.
The Christian name of the father was Piero (the son of Antonio the son of Piero the son of Guido, all of whom had been men of law like their descendant).
Of France came to Italy to conquer Naples Piero decided to assist the latter kingdom, although the traditional sympathies of the people were for the French king, and when Charles entered Florentine territory and captured Sarzana, Piero went to his camp and asked pardon for opposing him.
The king demanded the cession of Pisa, Leghorn and other towns, which Piero granted, but on returning to Florence on the 8th of November 1494 he found the opposition greatly strengthened and his popularity forfeited, especially when the news of his disgraceful cessions to Charles became known.
See Piero Maroncelli, Addizioni alle mie prigioni (Paris, 1834); the biographies by Latour; Gabriele Rosselli; Didier, Revue des deux mondes (September 1842); De Lomenie, Galerie des contemp. illustr.
The latter has other interesting pictures, including a fresco representing an apprentice with pestle and mortar (Pestapepe), the only authentic work in Forli of Melozzo da Forli (1438-1494), an eminent master whose style was formed under the influence of Piero della Francesca, and who was the master of Palmezzano; the frescoes in the Sforza chapel in SS.
Many adherents of the late prince came over to his side, disgusted by the violence and incompetency of Piero de' Medici's rule.
It was at his court that Piero della Francesca wrote his celebrated work on the science of perspective, Francesco di Giorgio Martini his Trattato d'architettura (published by Saluzzo, Turin, 1841), and Giovanni Santi his poetical account of the chief artists of his time.
He made his home with his elder brother Piero at Florence throughout the agitation of Savonarola and the invasion of Charles VIII.