Ogham Fews

Ogham is an alphabet of strokes cut across a stem-line, used to write Primitive Irish in inscriptions on standing stones, chiefly in Ireland and western Britain, from roughly the fourth to the sixth centuries CE. Each letter is one to five strokes, placed above, below or across the line, and each has a name.

The surviving stone inscriptions are mostly names and memorials. Medieval Irish scholars later elaborated the alphabet in manuscript tradition, attaching to each letter a tree, a bird, a colour and other associations in lists preserved in texts such as the Auraicept na n-Eces and the Book of Ballymote.

The association of the ogham letters with trees is genuine to the medieval Irish tradition, though not every letter is named for a tree, and it is this arboreal scheme that later writers, Robert Graves above all, developed into the modern "Celtic tree" lore and calendar. The atlas keeps the historical alphabet and its medieval glosses distinct from those twentieth-century constructions.

The entries give each letter its name, sound, and traditional associations. The letters are grouped into sets of five called aicmi, treated in their own category; the modern tree calendar is treated under the revivals.