A real initiation story is that of King Cormac Mac Art who was the most famous pagan king of Ireland.
This immram was written down in various manuscripts in the 14th and 15th centuries.
Cormac ascended the throne in 227 AD and according to the legends, with his fair stature and majestic appearance, he was an ideal king.
While standing alone on a hill in Tara, Cormac encounters an old gray warrior carrying a silver twig with three apples. From the branch sounds wonderful music that Cormac listens to with amazement. With the warrior's request to grant three wishes, Cormac can keep the branch. Then the old man disappears and the king returns to his palace. He tells the wonderful story, shakes his branch and the whole area falls into a deep and beneficial sleep for 24 hours.
After a year, the strange warrior returns and reminds him of his appointment.
I'll take your daughter and you must keep your promise,
says the old greybeard.
With a heavy heart, the king gives his daughter, whereupon the mother and the entire court break out in loud lamentations. The king shakes his special branch, the party falls into a deep slumber, and Cormac thus dispels the wail. A year later, the warrior comes to visit again and longs for his son. The same happens again, and only with the extraordinary branch does King Cormac manage to put a stop to the lamentation. For the third time, the old man comes to visit after a year and asks for his wife. The king gives her with great reluctance, but now he and all his court follow the warrior. Suddenly a thick fog sets in and King Cormac is alone. With surprise he discovers that the whole environment has changed: he has arrived in The Other World. He sees palaces of bronze and houses of silver. He also sees a spring that flows into five streams and from which people drink. Nine hazelnut trees grow at the source and drop their fruits into the water, where five salmon wait to eat them. What he finds most amazing is the music he hears here. At the well in the palace garden, he is requested by a woman to undergo a purification bath. Then the old man unexpectedly appears before him again and asks him to accompany him to a party. The king falls into a deep sleep to the singing of the partygoers and when he wakes up, he sees his wife and two children next to him. He discovers that the gray warrior is none other than the deity Manannan mac Lir who now offers him a magical shell that has the ability to burst into three pieces at the first falsehood.
Manannan tells Cormac that he invited him to his country so that he might get to know his country. He tells of the well of the five streams, from which everyone who desires wisdom should drink. The golden bowl would teach him to distinguish truth from falsehood, and the blossoming branch with its music would always give him joy. When Cormac dies, the branch and shell would come back to The Other World.
When the king wakes up the next day, he is back in Tara with his wife and children. Beside him in the grass are the silver branch and the golden bowl.
There is great joy in the court, for they thought that the king and his family had already died.
This story bears all traces of an initiation. The king must part with his loved ones; he is thus severely tested. Then he is led through a mist into The Other World in which he has to cleanse himself in the source. The sleep that overtakes him is the passing from one state of consciousness to another.
He eventually becomes aware that the old man who took his wife and children with him is the deity Manannan. Manannan tells him about certain things in The Other World and finally the whole family arrives again in their own kingdom.
The silver twig with the three golden apples reminds us of the Hesperides and the golden bowl is reminiscent of Celtic initiation cauldrons such as Gundestrup's and Ceridwen's cauldrons, which are discussed in more detail in the chapter on Taliesin.
The musical twig was an important part of the Celtic tradition. Thus the supreme poet, the ollam, had a golden branch, an anruth (was one degree lower than the ollam), had a silver branch and the lower class of poets had a bronze branch.
This branch was similar to the branch of the tree in The Other World.
The silver twig with bells belonged to the regalia of the poets and called for peace and harmony between this and the other world and propelled the listeners to mystical revelation.
The Immram of Bran
Finally, here is told the Immram of Bran which is a vivid description of striking beauty. Nothing in this Immram points to the drama of initiation as in Cormac's story. It's just a beautiful story with references to a world where paradisiacal peace reigned.
Bran, Febail's son, when alone one day hears wonderful soft music playing behind him. He listens to the lovely sounds and falls asleep.
When he awakens, he sees behind him a silver branch with white blossoms. He picks it up, takes her to the court and tells his experience there. Suddenly a strange woman in unusual clothes appears in the company. She begins to sing about The Other World, where golden chariots rise into the sea with the tide. With her beautiful voice, she tells about an island where happiness, health and joy reign. She tells extensively about the paradisiacal delights of this exceptional island. Then she leaves the company with the blossom branch she received from Bran, who has become very impressed.
The next day, Bran tries to find the magic island with his comrades.
While sailing, Bran meets the deity Manannan who comes to meet them in his magic chariot. Manannan predicts to Bran that it will take him a long time to see his beloved Ireland again. Bran sails on and arrives with his companions at an island, and its queen invites them for a year. In reality, it turns out to be many years. However, the adventurers get homesick and want to return to Ireland after a long time. They are let go, but they are not allowed to touch the earth with their feet. When they arrive in their beloved country, they tell their adventures from The Other World from their boat. The reactions of the people astonish them; people say they don't know them. The people know only in old tales Bran's journey with his adventurers! His comrades get angry and one of them jumps overboard furiously. Then the spell is broken and it immediately turns into a pile of ashes.
Then Bran tells his experiences of The Other World and he writes down the histories in the so-called Ogham script. He then hands it over to the people, and sails away with his friends, after which no one ever heard from him again.
 Caitlín Matthews, The Elements of Celtic Tradition, Element Books, 1989
 Hans Gsänger, Irland. Insel des Abel. Die irischen Hochkreuze [Ireland. Isle of Abel. The Irish high crosses], Verlag Die Kommenden, 1969