Francesco I Sforza
At the request of Francesco I Sforza, Pope Callixtus III made Castiglione a cardinal in the consistory of December 17, 1456. Castiglione entered Rome on February 23, 1457; received the red hat in the public consistory of February 24, 1457; and received the titular church of San Clemente on March 9, 1457.