Two hundred years BC, the Celts formed an immense civilisation in Europe, the Balkan and Asia Minor. They never built an empire, less countries or administratively organised regions. Their tribes were only gathered by language, druidic religion , an extreme love for art and a great respect of nature and its forces.
During the centuries they have had to give up the main part of their territories to Romans, Germans, Saxons and Angles. They withdrew in Ireland, Scotland, Wales, british Cornwall, Isle of Man, Brittany and Galicia, regions they still occupy.
Celts never fixed by writing any lawn, any cult, any tradition. So the Celtic civilisation in spite of its wealth and the size of its geographical extension remains not well known, especially by the general public: it cannot be find in history handbook. The knowledge and the cultural heritage are transmitted by word of mouth.
The oral tradition is still deeply alive nowadays by the Celtic peoples. The tradition is certainly for a great part in the persistency through time of the mutual feeling which animates Bretons , Irish, Welsh, Scots, Man's inhabitants, Galicians, and that paraphrasing Aimé Césaire, I like to call celtitude.