The festival of Samhain began the winter half of the year. It was believed that the Cailleach, the aspect of the Goddess who appeared as an old woman, hit the ground with her hammer, making it iron hard until Imbolc. On Samhain night, the gates of the otherword were open, and allowed communion with the ancestors who had passed on.

In the Christian era, the festival was reassigned to the Feast of All Saints, however many of the customs surrounding modern Hallowe'en still concern this ancient understanding of the accessibility of the dead at this time.

The ancestors were respected as the repositories of lore and wisdom; many Celtic tales speak of the dead returning to speak to their descendants in order to impart knowledge or to restore memory of ancient customs and stories.

The feast of both Samhain and Beltane were considered to be outside the boundaries of normal activities, when supernatural events take place; the barriers between humans, ancestors, gods and faeries are overthrown and they can visit each other's realms.

The modern festival of Hallowe'en, All Saints Eve, derives from the ancient Celtic festival of Samhain, called Nos Cyn Calan Gauaf in Welsh.

The Celts reckoned each twenty four hour interval from nightfall followed by day so that the fall of night brought the New Day.

Feast days are thus from twilight not from dawn.

Today, the Jewish faith also considers the day from sun down and not from midnight or dawn.

The preRoman Celtic sanctuary at Roquepertuse in Provence was entered through a trilithon stone portal in which were carved niches for human heads.

(A trilithon is a three stone form, two vertical, one across the top)

For the Celts, the seat of the soul was the head. These heads may have been those of fallen enemies, to be offered to the gods of the shrine.

The genius of Roquepertuse seems to have been depicted in the form of a goose or bird of prey. Within insular Celtic tradition, the raven holds the same function; this bird is associated with the Goddess of War, the Morrighan.

All Irish letters of the ogham alphabet are tree names.

Ogham was a method of straight line inscription which bisected the edge of a tone or stave of wood.

Many Irish texts speak of 'ogham libraries' or wisdom being preserved by some manner of encryption, decipherable only by poets and druids.

The writing of short messages or prophetic devices upon four sided wooden staves was a common method of communication over distance.

In the Irish tree alphabet, the letter A is represented by ailm, or scots pine trees

The Cailleach or 'veiled one' is the title given to the Goddess in her winter aspect. A caille is a veil, and the title is given also to nuns and as a respectful term to olde women or grandmothers.

There are a number of cailleachs of different Celtic regions, including the Cailleach Beare, the Old Woman of Feare, in South West Ireland, and the Cailleach Bheur or Blue Hag of Scotland.

Her cult is so ancient that only fragments of it exist, telling how she flew through the skies throwing stones out of her apron which fell to earth to become mountain rainges. She is the Old Woman Tossed Up in the Basket" from folk song and is associated in many regions with Mother Carey, who throws down the snows. She is frequently seen as at odds with Brighid, the Goddess associated with Imbolc but the stories reveal that the Cailleach renews her youth by changing as the seasons succeed each other.

In Wales, the Cailleach is called the Gwrach.