The Christians refused to do this and were persecuted. The sculptures of the dead reflect true portraits of the people. The sculptures of rulers are portraits, but tend not to reflect only rulers as youthful. The city of Pompeii, covered in 79 A.D. by an eruption of Mount Vesuvius, contains a wealth of paintings from the former Roman Empire. For wall painting the Romans used Fresco.
Fresco is a painting on uncured plaster.
This creates a durable surface which will not flake off unless the wall sustains water damage. These works show the great ability of the Roman artists to create the illusion of space . These paintings will inspire Renaissance realism. Much of these advances were due to their acquisition of knowledge from other cultures - Greek, Mesopotamian, and Egyptian. The Romans adapted the arch probably from Mesopotamia.