Three Mountains of Dewa
Over 1400 years ago in 593, Prince Hachiko opened the Dewa Sanzan mountains as a religious center, which is now considered the oldest history of mountain worship in Japan. After fleeing the Soga clan upon the killing of his father, Emperor Sushun, Prince Hachiko arrived in Dewa province, where he devoted the rest of his life to religious pursuits. He endured difficult ascetic exercises and a period of penance, leading to his worship of Haguro Gongen, the mountain deity. The prince began worshiping at the Gassan and Yudono mountains, leading to the enshrinement of all three deities at the temple on the peak of Mount Haguro.