The ancient mystery of the "sun at midnight," symbolizes the spiritual light that lies hidden within the dark. The Celts knew that light emerges out of darkness and so their days began at dusk, as if the sun was seeded in the black earth of night.
Next I saw the most lucid air, in which I heard in a marvelous way many kinds of musicians praising the joys of the heavenly citizens. ... And their sound was like the voice of a multitude, making music in harmony.