Fresco (plural frescos or frescoes) is a technique of mural painting executed upon freshly laid ("wet") lime plaster. Water is used as the vehicle for the dry-powder pigment to merge with the plaster, and with the setting of the plaster, the painting becomes an integral part of the wall. The word fresco (Italian: affresco) is derived from the Italian adjective fresco meaning "fresh”. This method is called buon fresco or, more commonly, a true fresco.
The oldest frescos done in this method are from the Minoan civilization and date from first half of the second millennium BC during the Bronze Age. The most famous of these, The Toreador, depicts a sacred ceremony in which individuals jump over the backs of large bulls. The oldest surviving Minoan-Cycladic frescoes are found on the island of Santorini (classically known as Thera), dated to the Neo-Palatial period (c. 1640–1600 BC).
Another, more common method, is called secco or fresco-secco.
A secco painting is done on dry plaster (secco meaning "dry" in Italian). The pigments thus require a binding medium, such as egg (tempera), glue or oil to attach the pigment to the wall.
The first known Egyptian fresco was found in Tomb 100 at Hierakonpolis, and dated to c. 3500 – 3200 BC. Ancient Egyptians painted many tombs and houses, but those wall paintings are not true frescoes. They were executed using the secco method on dry plaster.
An old fresco from Mesopotamia is the Investiture of Zimri-Lim (modern Syria), dating from the early 18th century BC.
While some similar frescoes have been found in other locations around the Mediterranean basin, particularly in Egypt and Morocco, their origins are subject to speculation. Some art historians believe that fresco artists from Crete may have been sent to various locations as part of a trade exchange, a possibility which raises to the fore the importance of this art form within the society of the times.