There are two main problems when looking at the evidence for the Celtic priesthood known as the Druids:
difficulties with the literary and archaeological sources
difficulties in sorting out the "truth" behind Druids and later literary invention
What does seen clear however is that the Druids belonged to a class that included high ranking holy men whose main function was to oversee the religious life of the community. Pomponius Mela called them the "professors of wisdom". Caesar also relates their judicial powers in matters of murder cases and other areas which affected "either individuals or the public".
Information relating to Druid ceremonies relates largely to sacrifice. Strabo tells us how victims were stabbed in the back and divination's made from their death throes, he also recounts other forms of human sacrifice including shooting to death by arrows or impaling and the burning of victims inside a huge wicker man. Caesar also writes of the wicker man whose background and meaning is still not explained. Tacitus refers to British human sacrifice on the Isle of Anglesey where, in a sacred grove, altars were drenched with human blood and entrails and consulted by the Druids for divinitory purposes.
The only detailed account of a Druid ceremony is given by Pliny who describes the cutting of mistletoe from an oak tree, a very rare occurrence. The rite was held on the sixth day of the moon and preparations were made for a feast and a sacrifice of two white bulls. A white robed Druid climbed the tree and cut the mistletoe with a golden sickle, which was caught as it fell on a white cloak. The bulls were then sacrificed.
Classical writers also provide us with some insights into the belief system of the Druids. Pomponius Mela tells us that the Druids believed "that souls are eternal and there is another life in the infernal regions", an item of Druidic belief echoed by other classical writers. As a class the Druids were also the repositories of much practical lore including knowledge of astronomy and calendrical computations. Caesar attributes the Druids with "much knowledge of the stars and their motion, of the size and shape of the world, the movements of the heavens and of the