More from John Truby:
King Arthur is not just a man and not just a king. He is the modern centaur, the metal horseman. As such, he is the first superman, the Man of Steel, the male taken to the extreme. He is the ultimate embodiment of warrior culture. He represents courage, strength, right action, and establishing justice through combat in front of others. Ironically, as masculinity taken to the extreme, he lives by a code of chivalry that places woman high on a pedestal of absolute purity. This turns the entire female gender into a symbol, divided into the Christian binary opposites of Madonna and whore.
King Arthur also symbolizes the modern leader in conflict. He creates a perfect community in Camelot, based on purity of character, only to lose it when his wife falls in love with his finest and purest knight. The conflict between duty and love is one of the great moral oppositions in storytelling, and King Arthur embodies it as well as any character ever has.
Arthur’s ally is Merlin, the mentor-magician par excellence. He is a throwback character to the pre-Christian worldview of magic, so he represents knowledge of the deeper forces of nature. He is the ultimate craftsman-artist of nature and human nature, and of human nature as an outgrowth of nature. His spells and advice always begin with a deep understanding of the needs and cravings of the unique person before him.
… If you want to use King Arthur symbols, be sure to twist their meaning so they become original to your story.
The Centrality of the Adventure Story, a quote from Marjery Hourihan