The protagonist of the poliptych is San Gimignano, bishop of Modena in the IVth century, and supposed protector of the tuscan city during a tragic war. The bishop, giving blessing, wrapped in a sumptuous red cape with gold punched work, holds a faithful model of the city with its wall, outer gate and slender towers, quite realistic in the rendering of architectural details. The vivacious lateral storiettes narrate episodes from the life of the bishop, famous for his great power against demons. Due to this particular reputation, he was called to the court of Constantinople to restore health to Emperor Gioviano's daughter. In fact, we see him, on the right side, embarking on a ship which, to the devil's meddling, is capsized by a storm; the nearby images show the saint liberating the emperor's daughter the demon that possessed her and, above, receiving gifts of gratitude from Gioviano.