Well, this question is kind of complicated and extensive. There were many golden ages throughout history, so there are thousands, maybe millions of inventions that were made in those years! Depending on which golden age you're talking about, there are different sorts of objects that we use nowadays. For example, during the golden age of the Roman Empire, laws were created. And we still use those laws, so that could be the answer to your question! Hope I was able to help. If you have any more questions, please let me know.
Adding onto SPARTANMAFIA’s answer they believed in manifest destiny where they thought they should have all of North America and that’s the way it should be