"The earliest undoubted occurrence of a zero in India is an inscription at Gwalior, dated Samvat 933 (876 A.D.). Where 50 garlands are mentioned (line 20), 50 is written
Aside from its appearance in early inscriptions, there is still another indication of the Hindu origin of the symbol in the special treatment of the concept zero in the early works on arithmetic. Brahmagupta, who lived in Ujjain, the center of Indian astronomy,[[190]] in the early part
of the seventh century, gives in his arithmetic[[191]] a distinct treatment of the properties of zero. He does not discuss a symbol, but he shows by his treatment that in some way zero had acquired a special significance not found in the Greek or other ancient arithmetics. A still more scientific treatment is given by Bhāskara,[[192]] although in one place he permits himself an unallowed liberty in dividing by zero. The most recently discovered work of ancient Indian mathematical lore, the Ganita-Sāra-Saṅgraha[[193]] of Mahāvīrācārya (c. 830 A.D.), while it does not use the numerals with place value, has a similar discussion of the calculation with zero.
What suggested the form for the zero is, of course, purely a matter of conjecture. The dot, which the Hindus used to fill up lacunæ in their manuscripts, much as we indicate a break in a sentence,[[194]] would have been a more natural symbol; and this is the one which the Hindus first used[[195]] and which most Arabs use to-day. There was also used for this purpose a cross, like our X, and this is occasionally found as a zero symbol.[[196]] In the Bakhṣālī manuscript above mentioned, the word śūnya, with the dot as its symbol, is used to denote the unknown quantity, as well as to denote zero. An analogous use of the
zero, for the unknown quantity in a proportion, appears in a Latin manuscript of some lectures by Gottfried Wolack in the University of Erfurt in 1467 and 1468.[[197]] The usage was noted even as early as the eighteenth century.[[198]]
The small circle was possibly suggested by the spurred circle which was used for ten.[[199]] It has also been thought that the omicron used by Ptolemy in his Almagest, to mark accidental blanks in the sexagesimal system which he employed, may have influenced the Indian writers.[[200]] This symbol was used quite generally in Europe and Asia, and the Arabic astronomer Al-Battānī[[201]] (died 929 A.D.) used a similar symbol in connection with the alphabetic system of numerals. The occasional use by Al-Battānī of the Arabic negative, lā, to indicate the absence of minutes
(or seconds), is noted by Nallino.[[202]] Noteworthy is also the use of the