http://www.andrews.edu/~calkins/math...ph/biozero.htm
Earliest use of zero is by the Iraqis.
The Original Use of Zero
The original use of the zero was formed by the babylonians. They used the sunya(zero) in the medial position to represent a blank spot for that individual set. The Zero in betweeen nagative and positive numbers wasn't invented until later when the chinese invented negative numbers.
The traditional Chinese numeration system is a base-ten system employing nine numerals and additional symbols for the place-value components of powers of ten. Before the eighth century A.D. the place where a zero would be required was always left absent. A circular symbol for zero is first found in a document dating from 1247, but it may have been in use a hundred years earlier.
The name for zero is not settled even yet. Older names and variations include naught, tziphra, sipos, tsiphron, rota, circulus, galgal, theca, null, and figura nihili.