Fun Fact:

The Dumnonii are an actual Celtic tribe which inhabited the south western tip of the British Isles.  In fact, old maps call the area Dumnonii.  Given the proximity to Ireland, and trade that existed between the two areas, Celtic ways prevailed much longer there than in other places in Britain. The beliefs of the Dumnonii were eventually wiped out due to the influence of the Catholic Church. Some of the customs, rites, and days of celebrations of the Celts were melded into Church rites and holy days. In this way, the transition from paganism to monotheism was made simpler for an uneducated peasant population. For example, the ancient spring fertility festival of the goddess Eoster became what we now call Easter.