If a man went back in time to this era with nothing more than a common knife, he could form a tribe and then an army and then rule the world.
There is a short story about that I read once. A man (somehow) was transported to 10’th century Iceland. He thought he would be king. But he was frustrated because he didn’t have access to the tools to make the tools he needed to make the stuff he knew how to make.
Mark Twain’s “A Connecticut Yankee in King Author’s Court” addressed this too.
I’m not so sure about that....
You can make lots of weapons from natural materials....
I’m not sure a common knife would get you very far...in ruling the world...
Considering hunters could bring down a wooly mamnoth with flint spears on a pole...