Although zero is defined as an integer, it is neither positive nor negative. Zero is the integer interval between positive and negative numbers, where an integer is defined as a non-fractional number.
The number zero was historically developed after basic counting systems. The first known recorded use of a symbol for zero was in ancient Egypt. Hieroglyphic accounting texts dating to 1740 B.C. use the symbol "nfr," meaning "beautiful," for a symbolic placeholder digit. It wasn't until centuries later that Indian mathematicians developed the concept of zero as a number. The "Brahmasputha Siddhanta," or "Opening of the Universe," written by Brahmagupta in A.D. 628, lists the mathematical operations of zero in a series of rules.