Until the 1950s, when Protestant proselytizers arrived, the Ilongot had had no contact with major world religions. The traditional belief system includes supernatural beings who are both helpful and dangerous. Illness is conceived to be caused by supernaturals who lick or urinate on the individual, by deceased ancestors, or by supernatural guardians of fields and forests who become angered by human destruction of what they guard. There are a few shamans who treat disease, and anyone so cured can use a portion of the shaman's spiritual power to cure; otherwise, spiritual curing power comes from illnesses and visions. The individual's spirit, which travels at night during his life, continues on after death. Since this spirit is dangerous to the living, it is forced away from habitations by sweeping, smoking, bathing, and invocation.