Then they made some leaps. Casting iron(copper) is relativly easy and powerful. Experiment with hot things in fire and you will discover it after a while. "W

Then they made some leaps. Casting iron(copper) is relativly easy and powerful. Experiment with hot things in fire and you will discover it after a while. "Why couldn’t they have use some natural form of biodegradable materials?" Like bones for bows and spears? Humans did that, but metal is apparently more effective and useful.