The history of the Museo delle Sinopie has a curious origin. In 1241 some cardinals who were going to Rome to depose Emperor Frederick II were imprisoned by the Ghibelline fleet of Pisa. Following this serious event, Pope Gregory IX excommunicated the entire city. To convince him to lift the excommunication, the Pisans, as an act of penitence, built the Ospedale di Misericordia, where the Museo delle Sinopie is currently housed.