Shamanism is very likely the oldest spiritual discipline in the world. The root word “s’ aman" can be translated "to burn up" or "to set on fire” referring to a shaman's ability to work with the energy of heat. Shamanism was practiced by the Celts and seems to have been an aspect of their Druidic training that was ultimately blended into the spiritual discipline of the Celtic Church. We can sense how connected the Celtic saints were with their ancient Shamanic forebears when we recall that the ability to handle either fire or hot coals was a skill frequently demonstrated by these saints.
In situations where information vitally needed for healing or survival was otherwise unavailable. a shaman would put herself or himself into an altered state of consciousness, during which the shamans’ soul would leave the body and make a journey. The shamans' souls would either ascend to the Upperworld or descend to the Lowerworld. There. among the inhabitants of those places. they would meet and confer with their "spirit guides" - either human or animal - who would help them either to obtain needed information or otherwise to achieve their journey's purpose.