Celtic spirituality had its beginning in Ireland and Scotland back as early as the third or fourth century. It is often frowned upon as being so focused on nature and creation that it is pantheistic. It is true that the Celtic Christians often baptized places and rituals associated with pagan Druid worship so that what was pagan became Christian, but what was embraced was not pantheism, but panenthesim. For example, some grove of trees associated with Druid worship was regarded as such sacred space that the emerging saints of Celtic spirituality re-imaged it into a sacred place for Christian worship.
One of the things which makes Celtic spirituality a unique creature of religious life is that it came into being without being under the influence of the institutionalized Roman Church. The theology developed by its saints was not influenced by Roman thinking; thus, what came into existence was an order of religious life not bound by the theology being developed by Augustine who preached total human depravity. Celtic spirituality looked into the face of the baby and declared that it was not evil which was present, but goodness. It was a faith established on the belief that there were two books of authority. One was the written Scripture and the other was the creation. One was the little book and the other was the big book.
It is not surprising that when the Roman culture began to move back into the regions of England after some two hundred years of being absent that there would be a theological clash. The conflict between the institutionalized Roman Church and Celtic spirituality came to a head in 664 at the Synod of Whitby. The outcome of the Synod affirmed the Roman tradition and the stream of Celtic spirituality began to lose influence until it became a fringe element in the religious life of the land and its people. It has only been in recent years that the practice of the Celtic traditions has found a new place in a church that has become so institutionalized that it could be losing its heart.