Bronze
Copper alloyed with tin makes a metal hard enough to replace stone — and a trade network to get the tin.
- When
- Known to
- ± 200 years
- Era
- Bronze Age, Holocene
Adding roughly a tenth part tin to copper produces an alloy far harder than either, castable into shapes stone cannot take and recyclable when broken. The difficulty is supply: copper and tin almost never occur together, and the tin used across the Near East came from Afghanistan and Cornwall. Bronze therefore forces long-distance trade, and the states that control it. When those routes fail at the end of the period, so does much else.