Ghent Altarpiece
Its authorship and dating have been particularly difficult to establish. For many years it was ascribed the only surviving work—excepting the "Ghent Altarpiece"—by Hubert, Jan van Eyck's older brother. Erwin Panofsky believed it a collaboration between the two men (similar to the "Ghent Altarpiece"); others see it as the c. 1440 output of a member of Jan's workshop, others again solely attribute Jan. Estimates of its date of completion range from 1410 to the year of Hubert's death, 1426.