Imperial diptych Imperial diptych In Late Antiquity, an imperial diptych is a theoretical type of ivory diptych, made up of two leaves of five panels each and each with a central panel representing the emperor or empress. They are so-named in contrast to consular diptychs. They were produced as unique examples, whereas each consular diptych was produced in large numbers to offer to the emperor on certain occasions, principally a nobleman's entry to the consulship. No complete example of an imperial diptych survives and so their existence is contested. The ivories specialist R. Delbrück has theorised that the 19 surviving fragments of
Beaune Altarpiece different. The figures occupy distinctly separate niches and the colour schemes of the grisaille saints and donors contrast sharply. Like many mid-15th century polyptychs, the exterior panels borrow heavily from the "Ghent Altarpiece", which was completed in 1432. The combination of naturalistic donor portraits with grisaille imitation statues of saints is borrowed from that work, as is the treatment of the Annunciation. Van der Weyden used iconography in the Beaune exterior panels not found in his other works, which suggests Rolin may have commissioned the altarpiece to follow van Eyck's example. Van der Weyden was not inclined merely to imitate