Diptych triptych form, with two outer panels that could be closed across the main central representation. They are one type of the multi-panel forms of painting known as "polyptychs". The diptych was a common format in Early Netherlandish painting and depicted subjects ranging from secular portraiture to religious personages and stories. Often a portrait and a Madonna and Child had a leaf each. It was especially popular in the 15th and 16th centuries. Painters such as Jan van Eyck, Rogier van der Weyden, Hans Memling and Hugo van der Goes used the form. Some modern artists have used the term in
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