Credit: Wikimedia Commons
Look closely at the map above and count the locations where Gold, Copper and Tin mines are identified by their markers shown in the map’s title box. I count seventeen (17) gold mines, eighty-three (83) copper mines, and only six (6) tin mines.
I’ll assume the availability of these three metals by weight is proportional to the numbers of their mines. Sure, you (and I) can challenge that assumption, but since neither of us has other data to make a better estimate, and I want to make a point about the economic value we can extract with straightforward analysis of the above map, I’ll proceed on the basis of my assumption.
There were three times (3:1) as many gold mines and fourteen times (14:1) as many copper mines as tin mines. This means this market is producing 14 tons of copper for every (1) ton of tin.
Bronze is an alloy of 88% copper and 12% tin by weight, which means you’ll need seven (7) tons of copper to mix with every (1) ton of tin to produce 8 tons of bronze. But there are 14 tons of copper in the map’s market for every (1) ton of tin. That means tin availability will only support conversion to bronze of 7 tons (50%) of available copper in the market, limiting the remaining 7 tons of copper to be sold as is or alloyed with something else. There wasn’t much else to alloy with copper except arsenic at that time, and it was deadly to its metallurgists.
Knowing supply and demand set relative prices, it’s clear that to make bronze weapons to defeat your adversary who has copper weapons, you’ll be willing to pay a high premium for tin weighing 12% of your copper—so that you can make bronze swords which will cut through your feisty neighbor’s copper swords. If the price for tin is proportional to the ratio of copper availability to tin availability i.e. at least 14 ⁄ 1 ≅ then tin will cost 14 times the price of copper, and you’ll be expected to pay in gold or gold equivalents per the barter market.
Of course, since having copper weapons against a bronze armed foe is close to suicide, you’ll probably be extorted by your tin supplier (“Get it while you can”) to pay an even higher premium. We all know the price is always higher when you’re desperate to buy.
If you don’t have enough tin to make all your metal weapons of bronze—word does get around—then you’re vulnerable to bronze armed predators. If you’re sane and not suicidal, you’ll likely pay much more gold (by weight) for the needed tin than just the simple ratio of copper to tin market availability i.e. much more that 14 times.
In violent times, you might be willing to pay more for tin than for gold because gold will have no value to you if you’re dead and will certainly end up in your conquering enemy’s purse, even if you are able to keep your life—if not your independence—by paying gold tribute to all bad guys who show up at your gate with sufficient numbers of thugs bearing bronze weapons.
So, the only real answer is to have sufficient thugs in your fortress bearing bronze swords, arrowheads, spearheads, maces, helmets, breastplates, and greaves so that passing gangs of thugs will look for easier prey.
Does that sound grim? Indeed, the situation grew ever more grim. That’s exactly what began happening in Old Europe as the Steppes horsemen encroached westward, acquired copper weaponry, and invaded with chariots and riders, beginning in the third millennium BC.
Thanks for visiting,
R. E. J. Burke
Take a look at Post 24 The Uluburun Shipwreck. Note that its cargo included 10 tons of copper and 1 ton of tin. That would have produced 8 tons of bronze weaponry and left 3 tons of copper in a storehouse. Hope the bronze armed bad boys didn’t show up at that king’s castle before he got resupplied and converted from copper to bronze!