Incantation plays traditional tribal music and South American music. It was formed in 1981, when a group of musicians, who were playing different types of music for the Ballet Rambert (now known as the Rambert Dance Company), volunteered to play for the ballet, Ghost Dances (also a name of one of their albums), about political oppression in South America. While they were rehearsing for the ballet, they were taught how to play authentic tribal/South American instruments and because the show was so successful they were given a recording contract. They chose to call themselves Incantation because their music is based on that of the Incas.
If you'd like to listen to more samples of Incatation's music, here are the links to their albums on Amazon:
Panpipes of the Andes, Panpipes From The Andes, Sergeant Early/Ghost Dance (this also has Celtic music on it), Dance of the Flames, On Gentle Rocks, Virgins of the Sun and The Meeting.