Many reasons that lead to war, economics is wrapped in virtually every one of them. 1066 and the Normans, not sure. There are some interesting, deep reads regarding the Spanish empire and the massive influx of Aztec gold and prices in Europe. Inflation raged for almost a century.
Means of exchange have been present in almost all cultures going back a few thousand years. Everything from shells to round rocks, bird feathers, etc. Gold and silver were settled on because the other means of exchange had a tendency to fall apart over time. Gold and silver just need a good shine and voila, back to normal.
Paper as a form of currency actually began with the Knights Templar and the first Crusade to Jerusalem way back when, roughly a thousand years. The Templars kept gold in their castles and in exchange for interest they would give a traveler an encoded receipt in England that could be cashed in Italy, Germany, France, Jerusalem, etc. This protected travelers, enriched the Templars, an order envowed to poverty.
Over time this grew into modern day fiat currency, inflation, fractional banking, bank runs, ruin, excess, war and the whole lot of it. When I use the "excessive monetary policy" don't confuse that for inflation. You have two tools, monetary and fiscal. Too much of one can be a bad thing. We have been in a run world wide for a few decades now, with a massive heap over the last decade. It would seem the devil may be coming due. One way out of this mess is a soft default. Others include war. The bigger the bubble, the bigger the mistake in trying to deflate reality.
Just my two cents.
Boo
