Druids filled the roles of judge, doctor, diviner, mage, mystic, and clerical scholar. In other words they filled the religious roles in their culture.

To become a Druid, students assembled in large groups for instruction and training, for a period of up to twenty years. The mythologies describe Druids who were capable of many magical powers such as divination and prophesy, control of the weather, healing and levitation. It was also believed that they were shapechangers and could take on the forms of animals. The Druids saw the Oak tree as special and thought that it gave special powers. They also worshipped the wren - telling the future by interpreting its flight. Unfortunately for the wren they believed that by eating them they could share in their powers.

Druidism must be understood in the context of the culture that created it. Only the Celtic people called their religious professionals Druids. Other cultures had other names for their clergy, and expected different duties from them. Druids were not an ethnic or cultural group in themselves, but part of a larger society in which they participated. In the pre-christian era of Celtic culture, the Druids were members of a professional class.