The earliest form of Irish writing is a system known as the Ogham (also spelled “Ogam”) Script. This first appeared about the 4th century C.E. and may be indigenous to Ireland. The Ogham Script was used from the 4th century through the 7th century, a period during which the Irish were converting from paganism to Christianity. While this system of writing is preserved today only on stones (about 350 are known to exist), archaeologists generally feel that it was probably done on wood as well.
Raise your hand if you think Tumblr should have an Ogham alphabet version. OK, I thought not. But if it did we would be among the first to sign up.