As writing was introduced by the Christian monks, ogham began to be written about in manuscripts, and the context is mostly grammatical. It seems that ogham was developed to an extremely complex degree; one source lists 150 different types of ogham, most either listing types of things (color ogham, river ogham, etc.) or comprising a different arrangement of the alphabet like a code, for example, putting the second section before the first and the fourth before the third. From mentions in the legend, it seems that ogham could be used as a simple, straightforward way of communicating that almost everybody could understand -- which makes sense if it was used as a gravestone. But in the hands of the Druids, ogham could be written in a code only they could understand, and used for secret communication.

For example, in one story, a particular warrior angers a king of Ireland and is banished. The king has his poet write (in ogham) on the warrior's shield that when he arrives he should be killed immediately. However, when the warrior gets to Scotland, having no clue what his shield says, he meets the Scottish king's poet. The poet takes a liking to the warrior, and tells the king that the ogham says the warrior should marry the king's daughter immediately. Which, of course, he does. That gives you an idea of the power that Druids/poets held in Celtic society, and having a secret language was certainly a part of that.

We talked a lot about what ogham meant to the Druids, parallels to ogham in other languages, and uses of the ogham today. Today, most of what's written about ogham is based on Robert Graves' The White Goddess, and isn't very historically accurate. However, I think ogham is still a useful system of divination, and knowing the history can make it that much richer.

-Morgan