The ancient priest class of the Celts: Druid's

Druid's Circle, Birkrigg Common
Originally uploaded by andy mcr.

In Celtic polytheism the word druid denotes the priestly class in ancient Celtic societies, which existed through much of Western Europe north of the Alps and in the British Isles until they were supplanted by Roman government and, later, Christianity. Druidic practices were part of the culture of all the tribal peoples called "Keltoi" and "Galatai" by Greeks and "Celtae" and "Galli" by Romans, which evolved into modern English "Celtic" and "Gaulish". They combined the duties of priest, arbitrator, healer, scholar, and magistrate, says Wikipedia.

The Druids were polytheists, but also deified elements of nature[1], such as the sun, the moon, and the stars, looking to them for "signs and seasons". They also venerated other natural elements, such as the oak, certain groves, tops of hills, streams, lakes and even plants, especially mistletoe and holly.

Fire was regarded as a symbol of several divinities and was associated with the sun and cleansing. Their calendar year was governed by the lunar, solar, and vegetative cycles. Archaeological evidence suggests that ceremonies were conducted to celebrate the two solstices and two equinoxes every year.[