Zeus, the youngest son of Cronus and Rhea, he was the supreme ruler of Mount Olympus and of the Pantheon of gods who resided there. Being the supreme ruler he upheld law, justice and morals, and this made him the spiritual leader of both gods and men. Zeus was a celestial god, and originally worshiped as a weather god by the Greek tribes. These people came southward from the Balkans circa 2100 BCE. He has always been associated as being a weather god, as his main attribute is the thunderbolt, he controlled thunder, lightning and rain. Theocritus wrote circa 265 BCE: "sometimes Zeus is clear, sometimes he rains". He is also known to have caused thunderstorms. In Homer's epic poem the Iliad he sent thunderstorms against his enemies. The name Zeus is related to the Greek word dios, meaning "bright".