Ogham

Ogham is the earliest form of writing in the Irish language, an alphabet of some twenty letters (later extended by a further five) in which each character is formed of one to five straight or angled strokes cut across, or on either side of, a central line, a "stem" that on standing stones is usually the vertical edge of the stone itself, read from the bottom up.

Several hundred ogham stones survive, chiefly in Ireland and in areas of Irish settlement in Wales, Scotland, and the Isle of Man, dating mostly from roughly the fourth to sixth centuries CE; most are memorial inscriptions giving a personal name and lineage, and they are among the earliest written records of the Irish language and important evidence for the transition from paganism to Christianity in Ireland. The letters bear the names of trees and plants in the later manuscript tradition (birch, rowan, alder, and so on), which gave rise to the modern notion of a "tree alphabet." Medieval Irish scholars treated ogham with great learning, the Auraicept na n-Eces ("Scholars' Primer") and the Book of Ballymote preserve elaborate systems and variant alphabets, and reported its use as a cipher and a mnemonic. In the modern era ogham has been widely adopted within Celtic-inspired Neo-Pagan and Druidic practice as a system of divination and correspondence, drawing on the tree-names and their symbolism. It is thus both a genuine ancient script of real historical and linguistic importance and, in its modern revival, a divinatory and magical alphabet.

The primary evidence for ogham is a few hundred inscribed stones, most of them in Ireland and a smaller number in Wales, Scotland, the Isle of Man and Cornwall, cut broadly between the fourth and the seventh centuries. Their contents are unromantic. Almost all of them record a personal name, usually in the genitive and often with a father's or a kindred's name attached, in the manner of a boundary or memorial marker. Nothing on them is divinatory.

The learned tradition about the letters is later and is written rather than carved. Medieval Irish scholars compiled lists of kennings for the letter names, and the grammatical tract known as the Auraicept na nEces sets out much of what is known about how the alphabet was understood by literate Christians several centuries after the stones were cut. Some letter names are tree names and some are not, and the strength of the association has been debated by philologists since.

The tree calendar familiar from modern books is a different matter again. Robert Graves set it out in The White Goddess in 1948 as a recovered druidic system of thirteen months, and he built it himself, working from the medieval letter lists and his own poetic reasoning. Scholars of early Irish rejected it immediately and have gone on rejecting it.

Divinatory ogham is therefore a twentieth-century construction on a genuinely ancient script, and the script's own attested use was to write names on stone.