The history of money concerns the development of social systems that provide at least one of the functions of money. Such systems can be understood as means of trading wealth indirectly; not directly as with barter. Money is a mechanism that facilitates this process.
Money may take a physical form as in coins and notes, or may exist as a written or electronic account. It may have intrinsic value (commodity money), be legally exchangeable for something with intrinsic value (representative money), or only have nominal value (fiat money).