Fiat (credit) came first. As trust in central authorities broke down, barter & convertible currencies came into vogue. A good book on the subject: http://www.

Fiat (credit) came first. As trust in central authorities broke down, barter & convertible currencies came into vogue. A good book on the subject: http://www.amazon.com/Debt-The-First-000-Years/dp/1612191290 http://www.amazon.com/Debt-The-First-000-Years/dp/1612191290