The Merode Altarpiece
Workshop of the Master of Flemalle. c. 1425 – 1430’s. Oil on wood panel, center 25.25 x 24 7/8″, each wing approx. 25 3/8 x 10 3/4″. Metropolitan Museum of Art, New York.
encyclopedia britannica
khan academy video
Workshop of Campin, Annunciation Triptych (Merode Altarpiece)