All Information That follows is adapted or taken from The Celtic Shaman By John Matthews.
To give an idea of the feel of Celtic Shamanism, here is a old story from Wales:
The Story of Talesin.
A young boy named Gwion Bach ( Gwion the Little) is set to watch over a cauldren by the Goddess Ceridwen.
The brew distilling within is intended for her son; the hideously ugly Afagddu ( Utter darkness). When drunk it will give him all knowledge, and the wisdom to use it. But while Ceridwen is absent, 3 drops of the liquid splash out of the cauldren onto Gwions finger. Sucking it to alleviate the pain, he imbibes the wisdom meant for Afagddu. But with this comes danger. Ceridwen, aware by her magic of what has happened, comes in pursuit of Gwion, who flees from her in the shape of various animals, birds and fish. Each time he assumes one form, Ceridwen assumes that of its natural predator.
Finally after a long chase, Gwion becomes a grain of wheat and Ceridwen in the form of a speckled red crested hen, eats the grain. Nine months later She gives birth to a beautiful boy, whom she cannot bear to kill and so she sets the child adrift in a leather bag on the sea.
Eventually, the boy fetches up in the salmon wier of Gwyddno Garanhir; where he is discovered by Gwyddnos hapless son Elffin. Upon opening the bag, he sees the bright forehead of the child and exclaims:
"Behold the Radiant Brow!"
Whereupon the child replies:
"Talesin be he called!"
( Tal-iessin=Shinning Brow)
He proceeds to give forth an extraordinary stream of inspired poetic utterance, prophecy and wisdom, the products of having imbibed the brew of inspiration.
He is taken back to Elffins home and becomes a famous bard and shaman.
This story has a shamanic nature which disguises an account of initiation and rebirth as changes into animal. bird and fish.
The initiation itself gives rise to great wisdom, which was afterwards ecoded in the poems attributed to Talesin. There we read not only of his transformation into other creatures, but also his symbolic relationship with the whole of creation.
This is a major objective of Shamans everywhere, and in the figure of Talesin and the teachings which have grown up around him, the primary elements of Celtic Shamanism are preserved.