Ogham

The ogham script is the written form of the old Irish language. It is thought of as a “tree” script as many of its characters are named after trees, and the form the characters take resemble the forked branches of a tree. The presence of the ogham script has been traced back to date as far back as two centuries BC. It’s believed that a lot of the found examples of ogham were coded messages to those still loyal to their old ways, easily read by those they intended to but indecipherable to Roman authorities.