Polygnotus was a Greek painter in the middle of the 5th century BC, son of Aglaophon. He was a native of Thasos, but was adopted by the Athenians, and admitted to their citizenship.

He painted for them in the time of Cimon a picture of the taking of Ilium on the walls of the Stoa Poecile, and another of the marriage of the daughters of Leucippus in the Anaceum. In the hall at the entrance to the Acropolis other works of his were preserved. The most important, however, of his paintings were his frescoes in a building erected at Delphi by the people of Cnidus. The subjects of these were the visit to Hades by Odysseus, and the taking of Ilium.

Fortunately the traveller Pausanias has left us a careful description of these paintings, figure by figure (Paus. X. 25-31). The foundations of the building have been recovered in the course of the French excavations at Delphi. From this evidence, some archaeologists have tried to reconstruct the paintings, excepting of course the colours of them. The figures were detached and seldom overlapping, ranged in two or three rows one above another; and the farther were not smaller nor dimmer than the nearer. It will hence appear that paintings at this time were executed on almost precisely the same plan as contemporary sculptural reliefs.

We learn also that Polygnotus employed but few colours, and those simple. Technically his art was primitive. His excellence lay in the beauty of his drawing of individual figures; but especially in the "ethical" and ideal character of his art. The contemporary, and perhaps the teacher, of Pheidias, he had the same grand manner. Simplicity, which was almost childlike, sentiment at once noble and gentle, extreme grace and charm of execution, marked his works, in contrast to the more animated, complicated and technically superior paintings of a later age.