The cuneiform (kjuːniːəfɔːm) script is the earliest known form of written expression. Created by the Sumerians from ca. 3000 BC (with predecessors reaching into the late 4th millennium Uruk IV period), cuneiform writing began as a system of pictographs. Over time, the pictorial representations became simplified and more abstract. Cuneiforms were written on clay tablets, on which symbols were drawn with a blunt reed for a stylus. The impressions left by the stylus were wedge shaped, thus giving rise to the name cuneiform ("wedge shaped"). The Sumerian script was adapted for the writing of the Akkadian, Elamite, Hittite (and Luwian), Hurrian (and Urartian) languages, and it inspired the Old Persian and Ugaritic national alphabets.