Ogham is an early Irish alphabet of twenty letters, each named for a tree or shrub and ordered into four groups of five. A reading in this report item works from the trees and plants a chart's placements correspond to, reading character through the qualities each named wood traditionally carries, rather than from letters drawn at random.

History

The script is attested primarily in stone inscriptions, mostly in the Primitive Irish language, found across Ireland and in parts of western Britain, and generally dated to roughly the fourth through sixth centuries CE, making it one of the earliest attested vernacular writing systems in the British Isles. Its core is twenty letters arranged in four groups of five called aicmi; five further supplementary letters, the forfeda, appear later and are less consistently attested across sources.

The tree name carried by each letter, and the fuller riddling kennings built around them, come from considerably later medieval manuscript sources, chiefly a body of texts called the Bríatharogaim, "word-oghams", preserved in manuscripts written centuries after the inscriptions themselves, so the tree associations are a genuine but later interpretive layer rather than something demonstrably present at the alphabet's origin. The popular modern picture of Ogham as a thirteen month tree calendar, in which a birth date determines a governing tree, is a distinct and much more recent construction: it does not appear in the medieval Irish material at all and was proposed by the poet Robert Graves in his 1948 book "The White Goddess", a work Celtic studies scholars widely regard as Graves's own imaginative synthesis rather than a recovery of attested ancient Druidic practice. This report item accordingly reads a chart against the trees each letter carries rather than presenting a fixed birth-date calendar as settled tradition.

The Four Aicmi

Aicme Beithe, Aicme hUatha, Aicme Muine and Aicme Ailme are the four traditional groups of five letters each, named for the first letter in each group.

The Twenty Letters

Aicme Beithe: Beith (birch), Luis (rowan), Fearn (alder), Saille (willow), Nion (ash). Aicme hUatha: Uath (hawthorn), Dair (oak), Tinne (holly), Coll (hazel), Quert (apple). Aicme Muine: Muin (vine), Gort (ivy), nGetal (broom or reed), Straif (blackthorn), Ruis (elder). Aicme Ailme: Ailm (fir or pine), Onn (gorse), Ur (heather), Eadhadh (aspen), Iodhadh (yew).

How A Reading Is Constructed

A reading works from a chart's placements rather than from letters drawn at random, pairing them with the trees and shrubs above and describing character through the qualities the tradition's later tree kennings attach to each wood, oak for strength, willow for flexibility, and so on. Because the specific mapping from birth date to a single governing tree is Graves's twentieth century construction rather than medieval Irish practice, this report item works from a chart's fuller set of placements instead of reducing a birth date to one fixed tree.

Where To Read More

• Aicme BeitheAicme Beithe, the first group of five.
• Aicme hUathaAicme hUatha, the second group of five.
• Aicme MuineAicme Muine, the third group of five.
• Aicme AilmeAicme Ailme, the fourth group of five.
• BeithAicme BeitheBeith: birch. First of Aicme Beithe.
• LuisAicme BeitheLuis: rowan.
• FearnAicme BeitheFearn: alder.
• SailleAicme BeitheSaille: willow.
• NionAicme BeitheNion: ash. Last of Aicme Beithe.
• UathAicme hUathaUath: hawthorn. First of Aicme hUatha.
• DairAicme hUathaDair: oak.
• TinneAicme hUathaTinne: holly.
• CollAicme hUathaColl: hazel.
• QuertAicme hUathaQuert: apple. Last of Aicme hUatha.
• MuinAicme MuineMuin: vine. First of Aicme Muine.
• GortAicme MuineGort: ivy.
• nGetalAicme MuinenGetal: broom or reed.
• StraifAicme MuineStraif: blackthorn.
• RuisAicme MuineRuis: elder. Last of Aicme Muine.
• AilmAicme AilmeAilm: fir or pine. First of Aicme Ailme.
• OnnAicme AilmeOnn: gorse.
• UrAicme AilmeUr: heather.
• EadhadhAicme AilmeEadhadh: aspen.
• IodhadhAicme AilmeIodhadh: yew. Last of Aicme Ailme and of the twenty core letters.