Ogham Explained: Ireland’s Oldest Writing, and What It Was Really For

A script made of strokes

Ogham (Irish ogam) is an alphabet designed to write early Irish. Its letters are groups of one to five strokes or notches cut across, or to one side of, a central line. On stone, that line is usually the natural edge of the slab — the arris — and the inscription is read along it, typically from the bottom upwards.

The classic alphabet has twenty letters in four groups of five, called aicmí (families). Each family is named after its first letter: aicme Beithe, aicme hÚatha, aicme Muine and aicme Ailme. A fifth group of extra symbols, the forfeda, was added later.

Where the stones are

Around 400 Ogham inscriptions survive. The large majority are in Ireland, and they cluster in the south — Kerry, Cork and Waterford above all. Others are found in Wales, Scotland, the Isle of Man and south-west England, often where Irish speakers settled.

Most were carved between roughly the fourth and seventh centuries AD. Some Welsh stones carry the same name in both Ogham and Latin letters, which is one of the reasons the script could be deciphered with confidence.

What they say

Almost all Ogham inscriptions are names. A typical formula is X MAQI Y — "of X, son of Y" — sometimes with a wider kin-group added. They were most likely memorials or markers of land and lineage. There are no Ogham poems on stone, no spells, and no prophecies.

Why the letters are named after trees

Later medieval scholars wrote about Ogham in manuscripts such as the Auraicept na nÉces ("the scholars' primer") and the In Lebor Ogaim ("the Book of Ogham"). They gave each letter a name, and many of those names are ordinary Irish words for trees and plants: beith (birch), dair (oak), coll (hazel), sail (willow), iodhadh (yew).

Not every name is certainly a tree. Scholars have argued, for example, that luis may mean "flame" or "herb" rather than rowan, and that úath means "horror" or "fear" rather than hawthorn. The neat "tree alphabet" is partly a medieval scholarly scheme, laid over an older script.

Ogham and divination: what we actually know

There is one well-known literary hint. In the medieval tale Tochmarc Étaíne ("The Wooing of Étaín"), a druid named Dalán cuts wands of yew, writes Ogham on them, and uses them to learn where Étaín has been taken. It is a story, written down centuries after the stones were carved — but it shows that medieval writers could imagine Ogham used in this way.

Beyond that, there is no surviving manual of Ogham divination. Modern Ogham "oracles", with sets of staves and fixed meanings for each letter, are twentieth-century creations. They can be meaningful tools for reflection; they are not a recovered ancient practice.

How Emerald Seer uses Ogham

We use Ogham as inspiration and say so. Our eight tree archetypes take their names from Ogham letters, and our descriptions of them are our own. When you see an Ogham letter on Emerald Seer, you are looking at real early Irish writing; when you read what an archetype "means", you are reading a modern interpretation.

If you want to see one

Many Ogham stones are on public view. There are notable collections at University College Cork and in the National Museum of Ireland, and stones still standing in the landscape across Kerry and the Dingle peninsula.