Crucifixion Diptych (van der Weyden) that they could be the left and center panels of a triptych, that they formed either the wings or shutters of an altarpiece, or that they were intended to decorate an organ case. The train of the Virgin's robe continues onto the right panel, which evidences that the panels were intended to lay side-by-side rather than separated (as the wings of an altarpiece would have been). Art historian E. P. Richardson proposed that they were the center panel of the lost Cambrai altarpiece (executed between 1455 and 1459), a single painting now split into two parts. Art historian Penny Howell
San Marco Altarpiece of cast shadows towards the bottom edges of the draperies in the painting, which are indicative of how Angelico gave the medieval equation of earthly and heavenly beauty new immediacy by translating it into the rational language of a representational style. In addition, as Angelico implies in other ways, glazing was a technique used to create yet another boundary between the real world and the pictorial illusion. San Marco Altarpiece The San Marco Altarpiece (also known as "Madonna and Saints") is a painting by the Italian early Renaissance painter Fra Angelico, housed in the San Marco Museum of Florence, Italy.