Conservation and restoration as concepts were already been known in ancient times. The earliest historic evidence is available from Hellenistic Greece, as well as from the early Roman Empire. The earliest historical sources mentioning conservation and restoration are:

Vitruvius (ca. 20 BC) in "De Architectura" (on wall paintings)
Plinius (23-79 AD) in "Historia Naturalis" (on wall paintings, marble, copper, bronze)
Pausanias (ca. 180 AD) in Book I, 154 (on bronze)

The modern history of conservation starts with the 19th century in Europe, focusing on oil paintings. Since 1945 international organizations like UNESCO, ICOM, ICCROM, and the IIC have been founded. In 1986/87 ICOMOS, ICCROM and UNESCO jointly adopted the "Code of Professional Ethics" in conservation; however, no international organisation has so far clearly defined what the requirements for the studies and training as a conservator/restorer are.