The earliest texts written in an undeciphered script by the civilization of Elam in the late 4th to early 3rd millennia BC. Like the early Sumerian writing, Proto-Elamite is pictographic and it may well be derived from the slightly earlier Sumerian script. Many of the Proto-Elamite clay tablets bear numerical symbols only and it is assumed that it was used for accounting and trade. Proto-Elamite tablets have been found over a surprisingly wide area of modern Iran: Warka, Susa, Godin, Sialk, Tepe Malyan, Tepe Yahya, Acropole, Sialk, and Shahri-I Sokhta and are usually associated with a distinctive ceramic assemblage and style of seal.