A tribe rose to power in very early ancient Greece - the Mycenaeans.
The Mycenaeans thought they were the best warriors in the world. They fought with everybody. They used stone weapons. They nearly always won. They did write things down, mostly boasting about their wonderful victories in battle. And they did have art, mostly art that showed warriors fighting with each other and with animals (with the Mycenaeans winning, of course.) So scholars do know something about these early people. Scholars learned from their writings and paintings that the Mycenaeans worshiped a great many gods, and built their homes on top of hills, to better defend them.
The Mycenaean age, or the time period in Greek history when the Mycenaeans were in charge, is sometimes called The Heroic Age. The Mycenaeans were very proud of their military heroes. They had that in common with all the early people who lived on the Greek peninsula.