Imperial diptych offerings to the emperor. However, the fact that the Barberini ivory was almost certainly not a diptych, but some kind of imperial icon without a second panel is a serious argument against the existence of the imperial diptych type. The two panels representing the empress Ariadne, in the Bargello in Florence and the Kunsthistorisches Museum in Vienna, also belong to the hypothesied imperial diptych type. They are the only central panels of such a diptych (other than the Barberini ivory) to survive, since all other fragments of such diptychs are from side panels. Imperial diptych In Late Antiquity, an imperial
Ildefonso Altarpiece was commissioned for the Brotherhood by his widow shortly after his death. Ildefonso Altarpiece The Ildefonso Altarpiece is a triptych painting by Peter Paul Rubens, dating to between 1630 and 1631. It is now in the Kunsthistorisches Museum of Vienna. It is named after the central panel, which shows Saint Ildefonsus's vision of the Virgin Mary, in which she gave him a "casula". On the side panels are Isabella Clara Eugenia and Albert VII, regents of the Spanish Netherlands, with their patron saints Albert and Elisabeth of Hungary. Albert had founded the Ildefonso Brotherhood in the church of Saint Jacques-sur-Coudenberg