Commissioned by bishop Angilberto II, the altar crafted by Volvinio is in the shape of a sarcophagus and it treasures the remains of the saint that can be viewed from an opening in the side towards the apse. On its front side, it is decorated with scenes from the life of Christ. The author has portrayed himself at the moment of being crowned by Saint Ambrose, in a panel at the centre of the rear side. Another panel shows bishop Angilberto offering a model of the altar to the saint. Again on the rear side, the artist has depicted the life of Milan’s patron saint.