What causes the sun to rise and set? Ancient Egyptians believed that the sun and various gods traveled the sky in a solar barge. The barge would travel the underworld at night, and at dawn rise up to travel the sky again. The Egyptians weren't alone in their belief in a sun god. Ancient Mesopotamians, Greeks, Romans and Aztecs all referred to sun deities. Learn more about what each civilization believed, and do research to find other societies or tribes who worshipped the sun.