The Celts were the first European people north of the Alps to rise from anonymity. They were never an empire, but they were a civilisation. Reviled for their barbarism and admired for their artistic craftsmanship, they shared a family of languages that are now the oldest living tongues in Europe. We reflect on the enigma of the Celts and examine the roots of their culture, unveiling its complex characteristics. Their tale extends from prehistoric Europe, through near obliteration by Rome, to a stumbling self-assertion as the second millennium drew to its close.