The large, multipaneled altarpiece is as controversial as it is admired. The controversy stems from an 1832 discovery (under a coat of paint on one of its outside panels) of a Latin poem that indicated that Hubert (1395–1441) had begun the work and Jan (c. 1370–1426) had completed it. So it was believed that The Ghent Altarpiece (1432) was a collaboration between the Flemish brothers. But the question of attribution continued to puzzle art historians for a century and a half as attempts to assign different parts of the polyptych (multipaneled work) to either of the brothers failed to gain acceptance. One art historian suggested that Hubert may not have been a painter at all, but rather a sculptor. This theory posited that Hubert’s contribution was only in crafting the frames—from which the paintings had been removed in 1566 and which were subsequently lost. However, scholars seem to have now reached the consensus that Hubert was largely responsible for the design of the altarpiece and for much of its execution, while Jan was the designer and painter of most of the figures. This elaborate altarpiece, which is composed of 20 folding panels, was typical of northern European art during the Middle Ages (500–1350). However, both van Eycks contributed to the flowering of Renaissance art in northern Europe as well.

In Jan’s works, which are finely detailed and ornamental (he was originally a miniaturist and illuminator), the progression from medieval to Renaissance art can be seen. In particular, his painting Man in a Red Turban (1433), which may be a self-portrait, marks an important step in the humanization of art. Prior to this, the artist’s subjects had been religious in nature; here the painting is simply a record of a living individual. This kind of portraiture began to multiply as artists and patrons alike became increasingly interested in the reality revealed by them. Through such portraits, man began to confront himself—rather than the “otherworldly anonymity of the Middle Ages.” Renaissance art—in Italy as well as in northern Europe—marks the “climax of the slow but mighty process that brings man’s eyes down from the supernatural to the natural world” (Gardner’s Art through the Ages).