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
St John Altarpiece (Memling) it presents a narrative, meant to emulate a vision the donors or viewers would experience when viewing the inside panels. Unlike most altarpieces of these types, Memling's fails to present a single unifying iconographical focus and is quite generalized with themes that seem unsuited for its specific location, according to Blum. She speculates the donors may have chosen the specific iconography, which "celebrated intercessory saints on the interior". It is an unusual painting in that it seems to "have served a double function: that of personal propitiation and that of public altarpiece, which portrayed the role of the religious community