Tahitian song, chant, and dance began as a way for people, who had no written language, to pass on the lessons they learned throughout their lives. Rhythms and poetry were used to help ingrain these lessons. The importance of mana, the life force that inspires people to overcome great challenges, was manifested by songs and stories of historic occasions: the nature and genealogy of royal families, voyages, wars, impressive athletics, passion, great sacrifices, and achievements. It was important for the Polynesian people to remember these stories and lessons. Stories of demi-gods and goddesses were crafted to represent the many examples of mana.