Didn’t the ancient Druids happily embrace the new universal religion?
In general the conversion of the people from cosmic religion to the newer universal religion in Celtic areas was peaceful with only a few notable instances of violently forceful conversion being reported. There also seems to be a popular belief that the conversion was sudden and happily embraced, when, in fact, it took several centuries to complete and as late as the tenth century C.E. we see examples of letters from leaders of the new religion urging that the Druids finally be put down completely. While the Druidic priesthood was slowly losing position as the new religious practice became culturally institutionalized we see that many of the other specialists in the Druid class continued many cultural practices within the new religion and right up into the seventeenth and eighteenth centuries with the great poetic and legal traditions schools surviving until the final oppression of the Gaelic Order in Ireland and Scotland.