The wings to the main section are missing; those on the upper sections, however, are dedicated to the Church and the Synagogue. Three scenes from the life of St. John, the Baptist are depicted: on the main section, we can see the moment when he baptises Christ, Our Lord in the waters of the River Jordan as an angel holds His tunic. Given its somewhat reduced size, the empty space above this scenario was probably reserved for a dove representing the Holy Spirit and, quite possibly, a bust of God, the Father surrounded by a host of clouds.
Two famous episodes of the saint's life can be seen on either side of the lateral sections: the scene on the left is of his martyrdom. In this, an executioner lifts his scimitar as he prepares to decapitate St. John whilst a kneeling Salomé, accompanied by one of her slaves, holds a tray in both hands, ready to catch his severed head. Both these figures reappear on the right section of the altarpiece in the scene depicting the Feast of Herod as he recoils in horror as Salomé places her trophy on the banquet table.