The Deity Hu is the spiritual, not material the sun in Celtic mythology, and he was married to the goddess Ceridwen. It represents the world soul and endows the human soul with visionary power. Hu elevated man to a state of expansion of consciousness in the spirit world, but not before the human soul had passed through the depths of darkness through Ceridwen to attain self-knowledge.
Ceridwen was a hard mistress, she is the initiated soul who can perceive the spiritual world. In order to make the human soul suitable for that perception, all kinds of tests and lessons had to be undergone in so-called ‘adventures‘.
In many stories, we read about certain objects that had to be found, which refers to a spiritual-alchemical secret. Some examples are the Grail cup that had to be found in the Percival story or the search for the Grail.
In many legends, the heroes embark on adventures on a ship made of glass. According to the poet Taliesin, Alexander the Great travelled in a glass boat, and Osiris’ ship was also made of glass. It is also said that Glastonbury was so-called because it was The Island of Glass, which was in a blessed state, having completed the quest for the grail.
Glass of some sort would have been the material with which the so-called ‘snake’s egg’, the famous talisman of the Druids, was made. According to Pliny, it could float on water and withstand the current like a boat.
Such is the great struggle for Truth, whose first efforts are related in Masonic tradition: the pouring of the sea of glass, the mystery of Melchizedek, and spiritual alchemy.
Ceridwen was the fertile mother of the world, the Demeter of the Celts, who created all things into being. Ceridwen had two sons and a daughter. One of the sons was called Morfran, the son of Serenity, and the daughter was Creidwy, the lovely maiden. The other son was the hideous Afaggdu, meaning darkness, which dwells within each of us and who must be redeemed. Ceridwen wants to help her son, and she brews a potion in the Cauldron that would “cure” her son. This will be discussed in more detail in the next chapter.
Hu, who bore the golden yoke of the sun, accompanied man on his journey from darkness into the brightness of the light. The Mysteries of Hu revealed the other pole of human existence: the ascent of the purified soul to the glorified state of consciousness in the spirit world.
Hu and Ceridwen have also been compared to the two colossal images in the Hibernian Mysteries, before which a disciple of spiritual knowledge was placed, having first passed through a period of rigorous preparation in which he discovered and experienced that the sense-world was an illusion without a real state of being. Likewise, man had to discover that the truth is hidden behind illusion and that true Being cannot be found in the sensory world.
Then when the pupil had experienced the tension of illusion and Truth in the depths of his soul, he was placed before two impressively large images and had to discover the world word. Seated in front of both statues, he had to decipher the world secret. Who sat in front of these images obtained soul experiences, a spiritual experience of how cosmos and microcosm interact.
With the male image, the solar column, he experienced the solar powers that could be felt deep in his blood. With the female image, the moon column, he obtained a rigidity, he experienced the earth winter and the lunar forces. He had to press the male image and experience that it was hollow and elastic in contrast to the female image, which was plastic when he touched it.
The two Hibernian images of sun and moon after a drawing by Steiner
Left alone with these gigantic images, the student became confused and had nothing but questions, questions, and more questions. In other words, he stood before the border to the spiritual world. You could compare this with a koan (an impossible question) that a Zen student had to solve for his master. Even the modern spiritual learner must go through these inner meditative experiences in order to approach the Truth, the truth that leads to the mystery of humanity and the world.
Finally, after a long period of time, the student, left alone, has the experience that the male image says to him, as it were:
I am the knowledge
But what I am is not a Being
The student got the shock experience that the ideas were just ideas without a real state of being, so: illusion. When he stood in front of the other statue, he was told:
I am the fantasy
But what I am has no truth
Thus, the pupil was confronted with the facts that the ideas were without a state of being, and fantasy was without truth.
And what is Truth? An immensely difficult question was asked here.
He had to dig deep into himself to find an answer.
Ultimately, man got to know himself as a microcosm, a spirit-soul being in conjunction with the macrocosm. He also learned to become, to weave, to arise and to perish in the macrocosm and to transform himself as if in a metamorphosis. This was an unprecedentedly important experience.
The greatest flowering of the Hibernian mysteries preceded the great mystery of Golgotha, and the disciples were, as it were, prepared for this mystery. They were prepared for the fact that everything in the course of world development tends towards the immensely important event at Golgotha. When the Christ dies on the cross on Golgotha, the Golgotha mystery is simultaneously experienced in images in the Hibernian Mysteries. In other words, on the Hibernian island, what happened before the physical eyes in Palestine was spiritually viewed. Thus, in Hibernia, the mystery of Golgotha was experienced spiritually, and this wondrous imagination elevated the humanity of that time with an internalization in the spiritual realm.
In connection with this, it should be noted that the Celts in Ireland adopted the Christian faith without any problem, because the Druids had already perceived the coming of Christ in a spiritual sense in their sacred mystery places. What had been expected for a long time had finally happened at some point, so resistance never occurred to the Celts!
There is a legend of the king of Ulster, Conchobar, who asks his Druid how it is that such a great force of nature has broken loose, because at the moment of the crucifixion heaven and earth tremble. The Druid answers him that the Jews have crucified Christ and that this act gives such a clearly recognizable sign.
Thus, on the Hibernian island, the images of the mystery of Calvary were experienced in a supersensory way at the same time as this mystery was unfolding in Palestine.
This was possible, because man at that time had a totally different consciousness than in later times.
However, the time of spiritual awareness passed when man increasingly needed outward and historically correct images. Moreover, the islands were eventually torn apart by invasions and strife and the shrines also degenerated. That was the end of Druid-Hibernian wisdom and fame. Only a few bards could convey by song and rune some of the wisdom, disguised in allegory and imagery.
Then came the time of a spiritual eclipse and that made man less accessible to supersensory influences.
 Rudolf Steiner: Mysteriengestaltungen [Mystery formations], GA 232 (1904), (English: rsarchive.org)
 Hans Gsänger, Irland. Insel des Abel. Die irischen Hochkreuze [Ireland. Isle of Abel. The Irish high crosses], Verlag Die Kommenden, 1969
 Eleanor C. Merry, The Flaming Door – The Mission of the Celtic Folk-Soul, Knowledge Books, East Grinstead 1936