See also the history of debt:<p>> <i>A major argument of the book is that the imprecise, informal, community-building indebtedness of "human economies" is only replaced by mathematically precise, firmly enforced debts through the introduction of violence, usually state-sponsored violence in some form of military or police.</i><p>> <i>A second major argument of the book is that, contrary to standard accounts of the history of money, debt is probably the oldest means of trade, with cash and barter transactions being later developments.</i><p>* <a href="https://en.wikipedia.org/wiki/Debt:_The_First_5000_Years" rel="nofollow">https://en.wikipedia.org/wiki/Debt:_The_First_5000_Years</a>