Kumano has been considered a sacred area since prehistoric times. Shinto, the native religion of Japan, started during prehistoric times as nature worship. And it was during this time when the sacred sites of Kumano were first created. When Buddhism was introduced into Japan in the 6th century, Shinto and Buddhism merged together. It was during this time when the belief that Kumano as a Buddhist Pure Land became prevalent (in the 9th and 10th centuries), the sacred sites as we know them today were formed.