Ogham or beth-luis-nion is a series of signs like our alphabet. Each sign represents a sound and is aligned to a tree (the sound is the first letter of the tree-name). there are about 20 signs, though some people have more. Ogham carvings were found on many stone monuments in Ireland and the U.K.

Ogham was a kind of alphabet, used mostly by druids and poets. In some stories great heroes, like Cuchulainn, or Danaan people, like Midir, know and use ogham as well. The Celts didn't write a lot down, even though they had this alphabet. They depended on their rich oral tradition and memory to tell and preserve the deeds of great heroes, the words of eloquent poets, the songs and spells of their culture. All this was taught from one druid to another, the tradition kept very alive this way (no dry books or confusing texts with a thousand interpretations between them). Ogham however did come in very handy at times. Sometimes poets (filidh) or bards, who had to memorize great and long texts, carved the first few letters of a story or poem in a wooden stick, to help remembering. The same thing could be done with the firt letters of laws to help the brehons, who carried those sticks around with them.

Ogham was used as well to mark important places and happenings. If some important battle had taken place, it would be carved into the next big stone and everyone passing would know.

Some heroes, as said, left messages for friends and foes using ogham (and knowing ogham was something very special). For example Cuchulainn left a message for the army of Maeve when they tried to invade Ulster. At that time he had just sent his father to warn the men in Ulster that there was an army coming, and he tried to buy some time. He was now on his own with the mission to stop an entire army. Fortunately, Cuchulainn wasn't only very strong, but very clever as well. So he decided to challenge them. A good challenge in those days, wasn't to be left aside, for pride and honor were very important.

Cuchulainn cut a small oak tree, and using only one hand and one arm, he wound a wreath of it. Aside the wreath he wrote his message in ogham: no one would pass until one man had made a similar wreath in exactly the same way.

When the army found this and the message, there was only one man who could decipher the ogham: Fergus mac Ronan. No one was able to repeat Cuchulainns trick and the army had to stay on their side of the wood.

Another use for ogham could have been magic: the signs were carved into small wooden pieces, who were thrown to the ground. the patterns that came out were said to tell the future. Caitlin Matthews writes more about this in The Celtic Tradition.

The ogham alphabet consisted of twenty signs (see below). Because they were carved, they were straight lines, a bit like runes. Each sign had the name of a tree and the first letter of the tree was the letter that the ogham stood for. Trees were very important, especially to the druids. Each tree had special attributes linked to it, and that influenced the meaning of the signs as well. I don't know all of the trees with their attributes and alignments, but I will describe the ones that I do know in other documents.

Please note with the Ogham signs that sometimes they were written with the central line going from left to right, instead of running straight down like in my pictures.

Ogham Sign	Ogham name	Tree
	Beth	Birch
	Luis	Rowan
	Nion	Ash
	Fearn	Alder
	Saille	Willow
	Huath	Hawthorn
	Duir	Oak
	Tinne	Holly
	Coll	Hazel
	Quert	Apple
	Muin	Vine
	Gort	Ivy
	Ngetal	Reed
	Straiff	Blackthorn
	Ruis	Elder
	Ailm	Silver fir
	Ohn	Furze
	Ura	Heather
	Eadha	Poplar
	Idho	Yew