Kasuga Taisha’s oldest existing document from the early 13th century, “Koshaki”, said that a shrine hall for four deities was created on November 9th in the year of 768 during the reign of Empress Shotoku, when Fujiwara Nagate was “Sadaijin” (Senior Minister)
Origin
In the beginning of the Nara Period (710 – 794), a deity called Takemikazuchi-no-mikoto was moved from Kashima Jingu Shrine (Ibaraki Prefecture) to the top of Mt. Mikasa in Kasuga, Nara, in order to protect the capital Heijo-kyo. A few decades later, in 768, the first shrine structure was built at the present site of Kasuga Taisha by Fujiwara-no-Nagate, one of the national leaders, and other people, according to an order of Empress Shotoku, who was also a relative of the Fujiwara Clan. Adding to the first deity, more deities were enshrined here, including Futsunushi-no-mikoto from Katori Jingu Shrine (Chiba Pref.), Amenokoyane-no-mikoto, supposedly an ancestor of the Fujiwara Clan, and Himegami, both from Hiraoka Jinja Shrine (Osaka Pref.).