From Yahoo Answers:
Before I answer the question directly, I have to comment that some of the same basic spiritual issues that we face today have been faced by seekers many thousands of years ago. So, in a way, our sense that we are at the crest of modernism and breaking new ground for the continuing enlightenment is only partially true. In many ways we may also be so advanced in some areas (such as our scientific and technical understanding of the world around us), that we have become morons on the spiritual plane. A good example of this is that western thinking barely acknowledges the reality of reincarnation. And all of those spiritual influences from the past (and perhaps the future) are at the core of who we are. This mindset (not shared by billons of non-Christian people around the world) thus shuts a major portal to self-knowledge.
So there were cultures and subcultures and people throughout history who really understood some fundamentals much better than we do even in our post-modern existence (and granted they may also have been clueless in other areas). And I have my own personal spin on the Percival legend that I haven't heard from other sources.
It is my belief that the story of the Fisher King is really about the journey to self-knowledge. That isn't the part that's so different. It's the grail castle and the Fisher King and the whole kingdom that is dying, well that is just a metaphor for us exploring our own inner kingdom and our own injuries. And of course that too is not new. But what I haven't heard before is that this whole realm is about dreaming and in particular lucid dreaming. In the dream we encounter our own character elements in the shadows which are both injured and potentially healing. When we become lucid by asking ourselves "Am I dreaming" that's where we get in touch with the powerful energy that can heal us. It's the truth (that comes from the dialog between conscious and unconscious selves) that sets us free. We have to take ownership in all of our archetypal manifestations in order to become whole and healthy integrated human beings. The Grail Kingdom then flourishes.
Source: Yahoo Answers: http://answers.yahoo.com/question/index?qid=20090125205155AAtpXDd