Something which might be helpful is long forgotten and detailed list of the
Civilopedia entries. By "detailed," I mean "complete," as in:
#TECH_Currency
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^Go to
www.civmods.com/content/aos.htm for a complete description of this item in the online Civilopedia. You will also find general instructions for AOS, specific instructions for this scenario, and a useful strategy guide.
#DESC_TECH_Currency
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^As cities grew, their internal economies became more complicated. People became specialists, some primarily producing grain, some pottery,
some bricks, etc. A system of barter developed, so that one individual's wares and services could be exchanged for those of another. Gold
and silver were widely used in such transactions, but the pieces needed to be weighed and tested for purity each time they changed hands. In
600 BC, the Lydians found a way around this problem. They began the practice of shaping electrum, an alloy of gold and silver, into pieces
of predetermined weight and purity, stamped with an official symbol. This idea caught on, and within 50 years all the important trading centers
of the world had adopted similar practices. The widespread use of currency created universal standards of value, allowing people from
various societies to conduct business almost anywhere without being forced to bring along bulky goods for trade and barter.
- Although, please do note that, in this particular case, the site "civmods.com" is very much extinct.