Tales of the Cailleach from throughout the Gaelic territories generally portray her as a very ancient female to whom is attributed the creation of features in the landscape, the husbandry of flocks and consequently the creation of tribes. Hills and mountains were considered parts of her body, rivers were a part of her essence. Still more mysterious was the manner in which her existence as the land itself became transmuted into the seasonal renewal cycles of the land in each solar year. She combines the consistent foundation-idea of ancient creation with that of annual renewal: as the New Year, the Blossoming Year, the Fruitful Year and the Dying Year. She was the soil that gave birth to generations of semi-divine/wild, semi-human characters in the oral culture's 'time before memory' and from which all ideas of survival-skill and nature-interaction derived down into those generations 'within memory'.
As a 'mother' goddess of nourishment and renewal she was associated with springs and rivers, and therefore the great ocean which received them. Many folk-tales exist about lakes being formed when she forgot to cap off a spring back in the mists of time when she was young. All of the world's rivers were believed by the ancients to flow into a 'world river', called Okeanos by the Greeks. At the limits of this great ocean-river was the spiritual Otherworld – ruled by Manannan in Gaelic myth. To the Greeks and Romans this was sometimes styled Elysium. It was bordered by a great river whose waters conferred forgetfulness to souls who would be reincarnated. The mysterious transition to the spiritual realm at the edge of this great ocean is a transition of water into the 'matter' state of spirit or aether, which ancients believed was the substance of the heavens and the otherworld. The ocean-river can be seen flowing in the heavens in the form of the Milky Way, on whose 'shores' the Cailleach (Orion) and her Bull (Taurus) are seen standing in the winter skies of the north. To complete its great cycle, this ocean-river was re-manifested from the cthonic recesses of the earth as fresh springs – just as spirits re-manifested from the sid mounds in old Gaelic belief. In ancient Atlantic religion throughout these parts of Europe, rivers had godesses – but as the rivers were all part of the same 'world river' these were identical, and the names effectively epithets of the 'one': Boand, Sinand, Seine, Avon, Aine… All one.
Each solar year is a triplicity of the 'three phases' of her earthly generative seasons, followed by a spiritual journey to see her consort in the Otherworld. At Imbolc she is the child (Bride), at Beltain the beautiful Maiden of golden flowers who leads the bull (Bui and Graine are some Haelic epithets), and Lunasa the productive but destructive mother – hunched (crom) like the reapers in the fields. From Samhain she goes to the sea to conduct her flock of 'children' to the next cycle of their existence in the otherworld, where the sun sets in the west. In this guise she is the 'hidden smith' reforging the world under the Earth ready for the epiphany of the new year when she comes again as Bride.
Her greatest mystery? She is a complementary reflection of Manannan in the Otherworld.