The Irish, Welsh, and Scots all have a Celtic ancestry, but they settled their respective regions before the Roman conquest of Britain.  There is an amazing amount of debate as to the origin of the Celts:  were they Phoenician?  stocky and dark?  tall and blonde?  as culturally cohesive as the label suggests?   The standard theory is that the Celts were an Indo-European group that gradually migrated across Europe and Asia, with an identifiable, distinct culture by 750 BC.  As a group, they were well-known to the Greeks and Romans. http://archaeology.suite101.com/article.cfm/archaeology_and_the_celts The Celts had arrived in Britain and Ireland by 400 BC, super-imposing upon whatever native peoples were already there.  The Celts in these regions, then, were on the fringes of Celtic culture, not their heart, which was centered in Northern Europe, particularly in what is now Germany, Austria, and Switzerland. Read more…