'nihil' translates to nothing, but 'nullus' translates to 'lack of' and was recognized and used as a number, even if the symbols didn't reflect this. Just because zero wasn't typically used when teaching mathematics (i.e. teaching quantity instead of number line) doesn't mean that there was no concept of 'zero' in the numerical sense. Both the romans and the greeks had concepts and proofs based around negativity and zero.

However, modern notation, including negative sign, zero, and algebra, are all rooted in eastern and middle eastern cultures.