The scariest thing about learning history just how much nothing changes.It's changed a lot. Several thousand years ago, we realized that having a king solves a lot of problems, such as tribal warfare, and squabbles between small groups of people. Pax Romana it might be called, although it was found on a smaller scale before that.
The Greeks appreciated the power of a monarch, but didn't like to be told what to do, and their emphasis on individual freedom eventually led to democracy like the Roman senate. Unfortunately, the roman senate couldn't handle changing demographics very well, and became indolent, corrupt, and useless, so a dictator was an improvement.
Throughout the middle ages, philosophers put a lot of thought into the idea of, "How to find the best monarch?"
Eventually the United States came up with an idea of how to balance the power of state with individual freedom, and put some procedures in place to handle demographic changes, learning from the Roman's failures.
Learning takes centuries, but it definitely happens. The improvements to the legal system since Sumerian times is notable as well.