'Celtic empire' implies that they had an emperor. Who was that then? Their culture was basically tribal and so quite disparite. Every so often a big tribe with a strong leader would impose their will over neighbouring tribes, but that doesn't define an 'empire'.

And how do we know that they had such an advanced culture. I suppose it's all that lost knowledge. But if they couldn't be arsed to invent writing (possibly a bit of a pre-requisite for an advanced culture). We'll never know. I mean - what have the Celts ever done for us? Surely the reason that Roman culture so rapidly overcame Celtic was that it was, well, better.

People who talk about 'celtic music' and think people who live in places where celtic languages are almost no longer spoken are the sole descendents of the Celts are living a strange dream. The Parisi were pretty big round here once, but I don't think of myself as Celtic, any more than I do Roman, Viking, Jute or Norman. All those people/cultures disppeared years ago, absorbed into the general mass of people. But I do love history and celtic art and Irish Mythology.