The Babylonians used a symbol as a placeholder to mark empty positions in numbers around 300 BC.

Ancient Babylonian mathematics had a base-60 number system. They used a symbol, like two slanted wedges, to show an empty spot in a number, helping to distinguish numbers like 1, 60, or 3600. However, they did not think of this symbol as a real number zero, just as a way to avoid confusion in writing numbers.