Brahmagupta (598-668) was an Indian mathematician and astronomer. He was the head of the astronomical observatory at Ujjain, and during his tenure there wrote two texts on mathematics and astronomy: the Brahmasphutasiddhanta in 628, and the '\'Khandakhadyaka'' in 665.
The Brahmasphutasiddhanta is the earliest known text other than the Mayan number system to treat zero as a number in its own right. It goes well beyond that, however, stating rules for arithmetic on negative numbers and zero which are quite close to the modern understanding. The major divergence is that Brahmagupta attempted to define division by zero, which is left undefined in modern mathematics. His definition is not terribly useful; for instance, he states that 0/0 = 0, which would be a handicap to discussion of removable singularities in calculus.