What is Ogham? The Tree Alphabet Explained
At its core, Ogham (pronounced ‘oh-am’) is an alphabet designed primarily to write the earliest known form of the Irish language, known as Primitive or Archaic Irish. Unlike the Latin alphabet, which is a collection of distinct characters, Ogham is a system based on tallies. The letters are formed by groups of one to five straight lines or notches, positioned relative to a central stemline (droim or druim). On the standing stones that are its most famous medium, this stemline is almost always the natural edge, or arris, of the stone.
The script is brilliantly systematic. The twenty original letters are organised into four groups, or aicmí (singular aicme). Each aicme is named after its first letter.
- Aicme Beithe (the ‘B’ Group): Consists of one to five straight strokes to the right of the stemline (or below, if written horizontally). Letters: B, L, V/F, S, N.
- Aicme hÚatha (the ‘H’ Group): Consists of one to five straight strokes to the left of the stemline (or above, if written horizontally). Letters: H, D, T, C, Q.
- Aicme Muine (the ‘M’ Group): Consists of one to five angled strokes that cross the stemline diagonally. Letters: M, G, NG, ST/Z, R.
- Aicme Ailme (the ‘A’ Group): Consists of one to five short notches or straight lines directly on the stemline. These represent the vowels: A, O, U, E, I.
To read an Ogham stone, you typically start at the bottom-left edge and read upwards, across the top, and down the right side if the inscription is long enough. For example, the name of a legendary hero, Lugh, would be carved as two lines to the right of the edge (L), followed by three notches on the edge (U), and then two diagonal strokes across the edge (G). A fifth group of more complex letters, the forfeda, was added later in the manuscript tradition to represent sounds not present in the original system.
Crucially, each letter is also named after a tree or plant, earning Ogham the romantic moniker “The Celtic Tree Alphabet.” B is Beith (Birch), L is Luis (Rowan), N is Nin (Ash), and so on. This deep connection to the natural world is a fundamental part of its character and cultural resonance.
Carved in Stone: The Ogham Inscriptions
The vast majority of our Ogham knowledge comes from over 400 surviving monumental stones, dating from roughly the 4th to the 7th centuries AD. These monoliths are scattered across Ireland, with the highest concentration in the southern counties of Kerry, Cork, and Waterford. They also appear in areas of Irish settlement across the sea, including Wales, Scotland, the Isle of Man, and even a single example in England.
What do these ancient stones say? They are not epic poems or detailed histories. Instead, their messages are stark, personal, and formulaic. Most inscriptions are memorials, bearing the name of an individual in the genitive (possessive) case, often followed by their patronymic. A typical formula is “X MAQI Y,” meaning “[The stone of] X, son of Y.”
For example, a famous stone from County Kerry reads “ANM CORBMACC MAQI DIBIR,” translating to “Name of Corbmac, son of Dibir.” These inscriptions are the earliest written records of Irish individuals’ names. They are genealogical markers, a way of claiming lineage and perhaps land. They function as gravestones, boundary markers, and statements of identity all at once, carving a family’s legacy directly into the landscape.
The Mysteries of its Origin
Where did this unique script come from? The exact origins of Ogham are a subject of spirited academic debate, adding to its mystique. Several compelling theories exist.
The most widely accepted theory suggests Ogham was created in the 4th century AD by Irish scholars who were familiar with the Latin alphabet. They may have designed it as a clever and suitable way to write the sounds of Primitive Irish, a language for which the Latin alphabet was a poor fit. The structured, tally-like system would have been easy to learn and remember in a culture with a strong oral tradition. It was a native invention, inspired by foreign knowledge.
A more romantic theory posits Ogham as a secret, cryptic alphabet created by druids or poets to communicate in a way that would be indecipherable to those outside their circle, particularly those familiar with Roman writing. This idea connects Ogham to a pre-Christian world of esoteric knowledge, though direct evidence for druidic use is scant. Another hypothesis even suggests it may have originated as a system of hand signals, using fingers against the bridge of the nose or shinbone as the stemline, which was later adapted for carving.
The truth is likely a blend of these ideas. Ogham was almost certainly created by someone with linguistic sophistication, designed specifically for the sounds of early Irish and the medium of stone and wood.
Beyond the Stones: Ogham in Manuscripts and Modern Life
While the standing stones are the primary artifacts, much of our detailed understanding of Ogham comes from later medieval manuscripts, most notably the 14th-century Book of Ballymote. It contains a tract called the Auraicept na n-Éces (“The Scholars’ Primer”), which treats Ogham as a venerable script on par with the alphabets of the classical world. These texts preserved the letter names, the “tree alphabet” connections, and various cryptic Ogham systems, ensuring the knowledge was not lost when the script fell out of common use.
Today, Ogham is experiencing a cultural renaissance. It has been reclaimed as a powerful symbol of Celtic, and particularly Irish, identity. You will find its elegant, linear forms in modern art, tattoos, and beautiful pieces of jewelry where names and meaningful words are rendered in the ancient script. It has moved beyond the windswept fields and churchyards to become a living part of contemporary Celtic culture.
To stand before an Ogham stone is a profound experience. You are not just looking at an old rock with scratches on it; you are looking at a name, a memory, a statement of belonging from over 1,500 years ago. Carved in stone and read on the edge, Ogham is more than an alphabet—it is a testament to Irish ingenuity and a direct, tactile whisper from the ancient past.
