h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The people who became Britons arrived around 1000-1500BC. They met with others whom they classed as 'giants'. The shamanistic culture of the Britons gave way to Druidism and a whole history was born. But what was that history? The Roman invasion saw the Brits slowly take on the mantle of greater glory and Celtic Christianity flourished along with the Old Ways of the Druid classes.
After Rome the west of Europe had the British stand against the invading English. There were 13 kingdoms in the north of todays England / south of todays Scotland. There was what is now Wales, Cornwall and Brittany.
What can we find from their 'histories', tales, songs, poems and language that may give us further sight of their culture/s and their true history? Not the English or Frensh version but the true version. Just a old British nobody researching millions of previous British nobodies. My websites on the Celtic Kingdom of Elmet are at www.oldtykes.co.uk and the newly started links between the Insular Brythonic lands and Brittany are at www.britt-gwenn-ha-du. All help and support gratefully accepted. John Davey