Although the stories of the Cailleach are essentially British, her origins are not. Exploring the earliest literary references to the Cailleach takes us to the classics of ancient Greece and Rome. References in writings by Herodotus, Strabo and Pliny suggest her worship as a Celtic tutelary goddess on the Iberian peninsula of Spain two and a half thousand years ago.

Moving beyond literature and focusing on the similarities in motifs, such as her giant size and stone-carrying, leads us to Neolithic Malta. There are distinct similarities between the Cailleach and the Maltese giantess Sansuna, credited by legend with building the Ggantija temples on the island of Gozo. These impressive buildings are the oldest religious structures in the world, predating monuments like the Pyramids and Stonehenge.

From such ancient Mediterranean origins, the Cailleach migrated with the Celts from Spain to Ireland, and on to Scotland and the Isle of Man. It is possible that her worship and stories also spread into the rest of Britain, hinted at in local folklore and place names. Thus we find possible echoes of her presence in England, Wales, and Jersey. The continental connection is also reinforced in shared motifs found in Brittany (France) and Scandinavia.

More than any other figure in Celtic or British myth, the Cailleach represents the cumulative power of time. Her great age is a common theme in many of the tales about her, and as a result she has almost always been seen as a hag or crone (a meaning of her name). Her earth-shaping ability, through accidental placement of great stones expresses a mythic explanation for processes which take millions of years. The deliberate placement of stones is frequently tied in with Neolithic burial chambers, hinting at the survival of a cult from the distant past.

The Cailleach also has strong associations with both the weather and water, being viewed as the goddess of the harsh winter months. In this role she has been linked in literature ad legend to the Celtic maiden goddess Bride, sometimes as polar opposite and at other times as being dual manifestations of the same goddess. The extent of her power was made clear when she exercised her control over the forces of nature, which made her a significant figure in local folklore.

The Cailleach was also particularly connected with animals in the role of Lady of the Beasts. In Ireland her favoured animal was the cow and in Scotland her particular animal was the deer. She was known to keep herds of her favourite animals and protect them from hunters, who petitioned her for assistance to be successful.

A possibility that must be considered is whether some of the Cailleach tales actually relate to a priestess cult. This process of apotheosis of mythical or historical figures, with their actions assimilated into a divine cult, would blur the boundaries between the Cailleach and her priestesses, were this to be the case. The existence of such a cult is not a new idea, as it was suggested in 1932 by J.G. Mackay in his The Deer-Cult and the Deer-Goddess Cult of the Ancient Caledonians. We have found literary references in records from the last two centuries which seem to substantiate the idea of a Cailleach priestess cult of wise women. However, as is often the case these hints ask more questions than they answer, leaving the reader to make up their own mind.

This blurring of boundaries is also seen with regard to other supernatural hag figures found across the British Isles. Some of these have been clearly identified with the Cailleach, such as Nicneven and Gyre Carling. Others such as Black Annis and the Old Woman of the Mountain share a number of motifs and may be derived from the Cailleach. Whilst this is an opinion we subscribe to, we have again presented the evidence for the reader to draw their own conclusions."

[From "Introduction"; Visions of the Cailleach, by Sorita d'Este and David Rankine.]