Portraiture's roots are likely found in prehistoric times, although few of these works survive today. In the art of the ancient civilizations of the Fertile Crescent, especially in Egypt, depictions of rulers and gods abound. However, most of these were done in a highly stylized fashion, and most in profile, usually on stone, metal, clay, plaster, or crystal. Egyptian portraiture placed relatively little emphasis on likeness, at least until the period of Akhenaten in the 14th century BC. Portrait painting of notables in China probably goes back to over 1000 BC, though none survive from that age. Existing Chinese portraits go back to about 1000 AD
From literary evidence we know that ancient Greek painting included portraiture, often highly accurate if the praises of writers are to be believed, but no painted examples remain. Sculpted heads of rulers and famous personalities like Socrates survive in some quantity, and like the individualized busts of Hellenistic rulers on coins, show that Greek portraiture could achieve a good likeness, and subjects were depicted with relatively little flattery - Socrates' portraits show why he had a reputation for being ugly. The successors of Alexander the Great began the practice of adding his head (as a deified figure) to their coins, and were soon using their own.
Roman portraiture adopted traditions of portraiture from both the Etruscans and Greeks, and developed a very strong tradition, linked to their religious use of ancestor portraits, as well as Roman politics. Again, the few painted survivals, in the Fayum portraits, Tomb of Aline and the Severan Tondo, all from Egypt under Roman rule, are clearly provincial productions that reflect Greek rather than Roman styles, but we have a wealth of sculpted heads, including many individualized portraits from middle-class tombs, and thousands of types of coin portraits.