In 1440, his fiefs in the Kingdom of Naples were occupied by King Alfonso I, and, to recover the situation, Sforza reconciled himself with Filippo Visconti. On 25 October 1441, in Cremona, he could finally marry Bianca Maria as part of the agreements that ended the war between Milan and Venice. The following year, he allied with René of Anjou, pretender to the throne of Naples, and marched against southern Italy. After some initial setbacks, he defeated the Neapolitan commander Niccolò Piccinino, who had invaded his possessions in Romagna and Marche, through the help of Sigismondo Pandolfo Malatesta (who had married his daughter Polissena) and the Venetians, and could return to Milan.