Apollo had as his purview the arts, prophecy, and healing. At his chief shrine at Delphi the watchword was "know thyself," the beginning and principal aim of human understanding. He is the god of rationality, harmony, and balance, known by the epithet Phoebus, "bright" or "shining," by which he is equated with the sun and more broadly the order of the cosmos. The adjective apollonian describes that which partakes of the rational and is marked by a sense of order and harmony. Its opposite is dionysian, which describes unbridled nature, the frenzied and the irrational. These polarities, the apollonian and the dionysian were recognized by the Greeks as twin.htmlects of the human psyche.