Francesco I Sforza
Born in Milan, she was the second daughter and last legitimate child of Galeazzo Maria Sforza, Duke of Milan, by his second wife, Bona of Savoy. Anna's paternal grandparents were Francesco I Sforza and Bianca Maria Visconti, for whom she was named. She had two older brothers: Gian Galeazzo Sforza and Hermes Maria Sforza, Marquis of Tortona, and a sister, Bianca Maria Sforza, second wife of Maximilian I, Holy Roman Emperor.