" Much later, the Seleucid Babylonians, who ruled over Mesopotamia as the successors of Alexander the Great, invented a symbol to replace this ambiguous ‘gap’ that the old Babylonians employed. Thus, the earliest known symbol for zero () is found on many Babylonian cuneiform clay tablets from around 300 BCE. "

― Jim Al-Khalili , The House of Wisdom: How Arabic Science Saved Ancient Knowledge and Gave Us the Renaissance