From about the 9th century BC written records begins to appear. And that make many city states. Besides introducing the coinage, a growing population and shortage of land also seems to have created internal strife between the poor and the rich in many city states. And the Olympic game has the most sway in the ancient Greece. According to legend, it was Heracles who first called the Games "Olympic" and established the custom of holding them every four years. A legend persists that after Heracles completed his twelve labors, he built the Olympic stadium as an honor to Zeus.