The Ancient Celts were not an illiterate people, but they transferred their knowledge orally. They had an alphabet of twenty letters called Ogham. Each letter was named after a tree from the land where they lived. Ogham was used on standing stones, primarily on graves and boundary markers.
The primary sources of information about the Celts are, in that light, the texts written by the Romans who were in touch with them and Christian
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showed last 75 words of 3950 total
never know with complete certainty.
Nonetheless, we try to find out, we try to shed light, to conclude. With the help of the sources that we can rely on – archaeological evidence, Romans and monks – we can make more theories, but they will still be only theories.
Caesar, Julius : De bello Gallico (Gallic Wars)
Ellis, Peter Berresford. The Celtic Empire
Bulfinch, Thomas. Bulfinch's Mythology: The Age of Fable, The Age of Chivalry, Legends of Charlemagne,