User blog:Withersoul/How would man have fought against the grim before using dust?

A little while ago I was thinking about rocks and minerals, which led me to think about iron weapons and tools.

Eventually I had a question which is how would man have fought against the grimm before using dust? Using our world as a point of refrence; they may not have had iron weapons as it took us humans a long time in civilization to figure out how to smelt copper and tin into bronze much less iron which came a while after that. Using the intro scene they said that they had removed the threat of the grimm and then made civilation. So I theorize that before they used stone weapons to try and fight the grimm. But this makes me wonder how they figured how to use dust in the first place. Because no metal means far less industrial machinery.

What do you guys think? Feel free to correct me I am wrong about something.