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
Heller Altarpiece Heller Altarpiece The Heller Altarpiece was an oil on panel triptych by German Renaissance artists Albrecht Dürer and Matthias Grünewald, executed between 1507 and 1509. The artwork was named after Jakob Heller, who ordered it. Dürer painted the interior, Grünewald the exterior. In 1615, Dürer copyist Jobst Harrich painted a duplicate, which is now at the Städel of Frankfurt. The side panels, executed by Bosch's workshop basing from his drawings, are at the Staatliche Kunsthalle of Karlsruhe. The painting was commissioned by Frankfurt merchant Jakob Heller, for the Dominican church of the city. In 1615, the central panel, the only