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
Pisa Altarpiece panels of the altarpiece, which is the only documented work by Masaccio, are in various museums. Scholars hypothesize the reconstruction of the altarpiece based on a very complete description by Vasari. The painting contains six figures: the Madonna and Child and four angels. The Madonna is the centre figure and is larger than any of the others to signify her importance. Christ sits on her knees, eating grapes offered to him by his mother. Although he is an exceedingly babyish baby (in comparison to the babies of Masaccio's immediate predecessors, like Lorenzo Monaco or Gentile da Fabriano), the grapes are