The Wayfarer, Hieronymus Bosch. 1510
“Dying Adonis,” Hendrick Goltzius. 1609
“Plato’s Allegory of the Cave,” engraving by Jan Saenredam, according to Cornelis van Haarlem. 1604,

In the dialogue from Plato’s Republic, Socrates describes a group of people who have lived  chained to the wall of a cave all of their lives, facing a blank wall.  The people watch shadows projected on the wall by things passing in  front of a fire behind them, and begin to ascribe forms to these  shadows. According to Socrates, the shadows are as close as the  prisoners get to viewing reality. He then explains how the philosopher  is like a prisoner who is freed from the cave and comes to understand  that the shadows on the wall do not make up reality at all, as he can  perceive the true form of reality rather than the mere shadows seen by  the prisoners.
The Allegory is related to Plato’s Theory of Forms, according to which the “Forms” (or “Ideas”),  and not the material world of change known to us through sensation,  possess the highest and most fundamental kind of reality. Only knowledge  of the Forms constitutes real knowledge.
Neptune’s Kingdom, printed by Jacob de Gheyn, published by Hendrik Goltzius. 1587
“The Large Turf,” Albrecht Dürer. 1503
“Portrait of a Young Woman,” Rogier van der Weyden. c. 1440
“Man in a Red Turban,” Jan van Eyck. 1433
Flower still-life, Hans Memling. 1490
“Portrait of Christoph Baumgartner,” (Detail) Christoph Amberger. 1543
Painted tabletop for Erasmus Stedelin, Martin Schaffner. 1533