There are several interesting books that deal with this topic – each of them written with a different authorial slant on who should get credit for zero (see, e.g. the ones by Kaplan, Teresi, Seife). What historians generally agree on is that zero started life as a “placeholder” in the positional number system of the Babylonians, who (by around 300 BC) started using two slanted wedge-like symbols to denote its presence (thus differentiating between 26 and 206, say). Later on, the Mayans independently devised a similar scheme for their own positional number system. The Chinese are also known to have used a blank space for zero in their counting system based on short rods (“rod numerals”). None of these civilizations, however, recognized zero as an actual number – that credit generally goes to the the Hindus (as ancient residents of the Indian subcontinent were called). The Bakshali manuscript mentioned in the “Who invented zero?” article definitively establishes that the Hindus were using zero as a written number in the third or fourth century AD.
What’s interesting is that the Greeks, recognized as the greatest contributors to mathematics in antiquity, let zero slip through their fingers. Apparently, they had inklings of it, but were too much under the sway of Aristotle, whose philosophy was hostile to the existence of a void. Consequently, they were uncomfortable with the concept of zero, even frightened of it, and always kept it at arm’s length. The Hindus, on the other hand, practiced a religion in which the void was exalted, since it was the source from which everything emerged. This openness may have contributed to their recognition of zero not just as a placeholder but a full-fledged, free-standing number. As a result, when the Arabs transferred Hindu numerals to Europe, the symbol for zero (or “shunya” as it is called in Sanskrit) was included.
It still took a few more centuries for zero and the numerals to be accepted in Europe (with the local government in Florence even banning their use in 1299 – see e.g. Seife). But by the 1400s, most opposition had died down, and the numbers as we know them today were in common usage.
Discussion: The start of “The Godfather of Numbers” asks you to imagine a world without numbers. What would happen if only zero were to disappear from your world, but the other nine digits remained? Related to this, where would our civilization be if zero was still not recognized as a number in its own right?
The Big Bang of Numbers (video)