Literary evidence of the colonization of south Wales is preserved both in Welsh and Irish sources, and some idea of the extent of Irish oversea activity may be gathered from the distribution of the Ogam inscriptions in Wales, south-west England and the Isle of Man.
This he accomplished by means of four wands of yew inscribed with ogam characters.
Professor Rhys, who at one time considered runes and ogam to be connected, now thinks that ogam was the invention of a grammarian in South Wales who was familiar with Latin letters.
The Greek alphabet, with which it was most Symbols of Ogam Alphabet.
An interpretation of the oldest ogam inscriptions is given by Whitley Stokes in Bezzenberger's Beitrage, xi.
From this system probably developed the ogam writing employed among the Celtic peoples of Britain and Ireland.
The ogam inscriptions in Wales are frequently accompanied by Latin legends, and they date probably as far back as the 5th and 6th centuries A D.
However this may be, the ogam alphabet shows some knowledge of phonetics and some attempt to classify the sounds accordingly.
Four stones with Ogam inscriptions have been found at different places.