:::Who said that royalty, politicians , bankers and merchants were logical? Money is a commodity not a measure. It's worth what people think it's worth. Distance, temperature and volume can be defined by standards. 'Weight' is dependent on gravity, but as we spend most of our time on the surface of this planet the 'mass' measurement will suffice as a standard. How can you have a standard that is fixed and never-changing for money? The nearest I can think of in terms of money measurement is the Mars Bar standard sometimes used here in the UK. But even that fails as relative prices of other products have changed differently. PCs were around £1000 to £3000 at one time. The one I'm using here cost £110 - new earlier this year. Mars Bars have increased in price... The only standard for money is to arbitrarily take one commodity and use that. Gold, silver, copper, cattle, cowrie shells, iron, all these have been tried. Iron rusts. Cowrie shells can be imported from their beaches. Cattle can be bred - and can also die of disease. Copper is common and easily smelted. Gold and silver had the advantage of being relatively useless, distinctly pretty, and fairly corrosion-free - and there wasn't much of them around. The Spanish imports of gold from the New World did very nasty things to their domestic economy and that of the rest of Europe too. Gold was a practical standard once. When it was rare. But, when you give up carting gold around and switch to using bits of paper representing gold, you are reaching the faith test. Do you believe that the Blankshire Bank has the gold in its cellars? If you don't know, you have to depend on reputation. Read Terry Pratchett's book 'Making Money'. Very funny, but with a lot underneath the comedy. (You may need to read 'Going Postal' first, but maybe not. They're all well worth reading anyway.) I won't give the plot away, but it is very relevant to this discussion.