I'm really bad at Thesis Statements of stuff. Can someone help me with one 'bout a story about the aztecs?

I've read the story many times, I know the details. I just don't know how to create a thesis statement, or like explain the conclusion or argument. however you call it. Cortez ended up being able to manipulate and conquer the Aztecs , steal their treasures. But that sounds just dumb. lmao. I need help! Its from An American History Reader, Vol. 1, Chapter 1 "Cortez and Montezuma" by Allen Weinstein