It is said that the shrine was founded in the Yuryaku era (around 470) of the Yamato period. It is one of the oldest shrines in Japan, enshrined for the protection of the Kawachi region.This Jinja is one of Myojin-Taisha in the Engishiki.
「恩智神社圭田八十三束三字田所祭手力雄神也雄略天皇三年奉ニ圭田一行ニ神事一云々」
と記されています。( 総国風土記 )
After this Jinja was rebuilt by the Fujiwara clan in the Nara period (around 760), the ancestral kami of the Fujiwara clan, Amenokoyane-Mikoto, was transferred from the present Katori Jingu in Hitachi Province, and the Jinja was built as a Subsidiary Jinja. Later, in around 770, the kami was enshrined in Nara (Kasuga Taisha) via Hiraoka (Hiraoka Jinja). This is the reason why this Jinja is called Moto-Kasuga. Also, when Jingu Kougou went to the continent to fight, the kami of this jinja, together with the kami of Sumiyoshi Taisha, protected the safety of the land and sea routes, and acted as her spearhead or rear guard. Since then, this Jinja has been highly revered by the Imperial Court, and the Tennou has visited here on numerous occasions to pray.
In April 994, Ichijo Tennou sent the Nakatomi clan as an envoy to pray for protection from plague and other misfortunes. This is said to be the beginning of the purification ritual, the summer festival, at this Jinja. Also, this Jinja was originally built in Tennou-no-mori (Village Shrine), but about 700 years ago, when Sakon Onchi built Onchi Castle, the Jinja was moved to its current location on Onchi Mountain because it was considered impolite to have it above the Jinja.