Sumerian Cuneiform circa 2500 BC. Clay tablet with summary account of silver for the governor. From Shuruppak or Abu Salabikh, Iraq, circa 2,500 BCE. British Museum, London. BM 15826 In 3500 BC the Sumerians had a well developed writing system. Possibly the first writing system. Initial over 2000 symbols, pictograms and drawings were used.