The base of a cup which shows graffito - an incised mark, usually in the form of letters or numbers but also sometimes words and phrases. When such marks are painted they are called dipinto. The marks may indicate prices, trademarks and ownership or have been used by potters to match vessels with lids after firing. They most often occur under the foot of pottery vessels. This example is from Attica, c. 490-470 BCE. (British Museum, London).