>They place the oldest copper working in Serbia, though the fertile crescent is not far behind Oh that's interesting, I genuinely hadn't known that. Otzi the iceman was also found with a lot of arsenic on his skin, leading to speculation he might have been a copper worker. He also had a copper axe which would have been the ferrari of tools at the time. >As for America, it seems like they would use copper but only cold-forge it, which is also how they used gold. So they never made the leap to actual metallurgy. Ah! Fair enough. I suspect pottery might have been the key preceeding technology which leads on to metallurgy. Amerindians did have pottery, but it was nowhere near as much a core technology as in the near east and eastern mediterranean. >You're mistaken. The Manchus and the Jurchen are the same, and they're outsiders similar to the Mongols. The order of dynasties goes Song (Han) -> Jin (Jurchen) / Southern Song -> Yuan (Mongol) -> Ming (Han) -> Qing (Jurchen later renamed to Manchu). So the pattern is repeatedly native rule leads to wealth but then degeneracy, followed by foreigners conquering them, which leads to suffering but then national resistance followed by chaos until a new native hegemon rises. So they've fought a number of guerilla campaigns against outsiders, but usually only after the outsiders got weakened by luxury and court intrigue. They could never beat the people who were born into the saddle, but they could beat their sons who were born in a harem. Sorry, I didn't mean to imply that was the correct order of dynasties. My point was more that any reigning chinese dynasty was subject to the same weaknesses as it's predecessors and tended to be conquered for the same reasons. I'd argue that's different to being inherently vulnerable to guerilla war.