This Babelstone post on Byrhtferth’s Ogham Enigma is fascinating, detailed, and includes great images.

It probably comes as a surprise to most people to find out that the earliest extant manuscript to include any text written in the Ogham script is an early 12th century English manuscript copy of a work by the late Anglo-Saxon monk Byrhtferth (Byrhtferð) rather than one of the more famous Irish manuscripts that include descriptions of the Ogham script, such as the Book of Ballymote or the Yellow Book of Lecan. But although the origin of Old Irish texts about Ogham such as Auraicept na n-Éces (“The Scholar’s Primer”) and In Lebor Ogaim (“The Book of Oghams”) undoubtedly predates Byrhtferth’s work, the only extant manuscript copies of these texts are later than the Byrhtferth manuscript. [continue]

Byrhtferth was a monk who worked at the Abbey of Ramsey in Huntingdonshire during the late 10th and early 11th centuries. He is mainly remembered for his Enchiridion or Handbōc (Ashmolean MS 328), a work on the arts of computus and numerology which exhibits an obsession with ordering the universe on a numerological basis. Various other texts derived from a now lost computistical miscellany by Byrhtferth are preserved in two other manuscripts: [continue]