The worship of great mountains as embodiments of mysterious power was a major element of ancient Chinese culture. Such sacred mountains were deemed dangerous at first, prohibitive places where heavenly and earthly spirits mingled with ferocious animals and monsters. Eventually they were seen as the dwelling places of divinities and were woven into Chinese state religions. Five Sacred Mountains, one in each cardinal direction, came to define, control, and protect China’s physical and sacred realms.
To adherents of Daoism, which emerged as an organized religion during the second century CE, the great mountains were considered especially suited to mental concentration and the preparation of drugs of immortality. Caves and hollows within the sacred mountains came to be seen as a network of grotto-heavens known as the dongtian, the abode of supernatural beings.
This image of a realm of immortals developed into that of a fantastic world of mountains and valleys, sometimes dotted with beautiful palaces where immortals happily lived in perpetuity.