Hugo van der Goes (c. 1440 - 1482), The Lamentation, c. 1479, oil on panel, Kunsthistorisches Museum Wien, Gemäldegalerie.

Hugo van der Goes (c. 1440 - 1482), The Fall of Man (verso: Saint Genevieve), c. 1479, oil on panel, Kunsthistorisches Museum Wien, Gemäldegalerie.

Robert Campin (c. 1375 - 1444), Christ Blessing with the Virgin in Prayer, c. 1425 - 1430, oil and gold on panel, Philadelphia Museum of Art, John G. Johnson Collection, 1917.

Albert Bouts (c. 1452/1455 - 1549), The Annunciation (The Virgin Annunciate and The Angel Gabriel), c. 1495, oil on panel, Suermondt-Ludwig-Museum Aachen.

Jean Bellegambe (active 1504 - 1534), Saint Bernard and a Cistercian Monk (verso: Jeanne de Boubais), c. 1507/1533, oil on panel, Frick Art & Historical Center, Pittsburgh.

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Two panels of an early 16th-century diptych by Michel Sittow are reunited : left, Gemäldegalerie, right, Berlin; National Gallery of Art, Washington

Jan van Eyck, “Annunciation” diptych (1430), Museo Thyssen-Bornemisza, Madrid

“Ecce Homo,” a panel in oil from about 1525 by Albert Bouts (Suermondt-Ludwig-Museum Aachen)

Nicolas Froment, portraits de René 1er, Duc d'Anjou et de Jeanne de Laval, circa 1476-1479, huile sur bois, Musée du Louvre, Paris.

"Christ Taking Leave of His Mother" by Gerard David, circa 1490-1495, oil on panel, Kunstmuseum Basel

Left, "Virgin and Child," and, right, "Three Donors," by Master of the Saint Ursula Legend, 1486, oil on panel, Koninlijk Museum voor Schone Kunsten

Left, "Virgin and Child," and, right, "Willem van Bibaut" by Master of the Magdalen Legend, 1523, oil on panel, private collection.

Bernard de Rijckere, portrait of Adriaan van Santvoort and his sons, Guillaume and Adriaan, 1563, oil on panel, private collection

“Prayers and Portraits: Unfolding the Netherlandish Diptych” remains on exhibition at the National Gallery of Art, between Third and Seventh Streets at Constitution Avenue, Washington; (202) 737-4215, nga.gov, through Feb. 4.