Jimyoin-to was Japanese Imperial Family ancestry between the late Kamakura period and the Southern and Northern Courts period and is a descendant of the eighty-ninth Emperor Go-Fukakusa, whose father was the eighty-eighth Emperor Go-saga.
The name Jimyoin-to came from the Buddhist temple built in his palace by FUJIWARA no Motoyori, a general of Chinjufu; it was called Jimyoin, and the entire family was called the Jimyoin-to Family.
Nobuko, the daughter of Motoie JIMYOIN and the grandchild of Motoyori, became the wife of Crown Prince Morisada and, because three retired emperors were sentenced to exile after the Jokyu disturbance, Crown Prince Morisada's son Imperial Prince Yutahito was enthroned as emperor (taking the name Go-Horikawa) in accordance with the instructions of the bakufu (Imperial Prince Morisada received the respected name of Dajo Tenno and was later called Go-Takakurain). Emperor Go-Horikawa named and lived in the Jimyo-in palace as Sento Imperial Palace; and the retired Emperors Go-Saga and Go-Fukakusa lived in the same palace. Accordingly, the line from Emperor Go-Fukakusa to Emperor Go-Komatsu is called Jimyoin-to.
The retired Emperor Go-Saga, who started a cloister government, left a will for the brother of the retired Emperor Go-Fukakusa, Emperor Kameyama's descendant (Daikakuji-to), to succeed to the Imperial Throne, and this caused the mutual conflict; therefore, it was decided by the Kamakura shogunate to share the Imperial Throne between ancestors from both sides on the basis of a rotation every 10 years (Ryoto Teiritsu) and to continue running the cloister government.
Apparently, the royal heritage was unified by Daikakuji-to after the start of the Kemmu Restoration by Emperor Go-Daigo, who was from a minor member of Daikakuji-to; however, the new government collapsed after two-and-a-half years. After Emperor Go-Daigo escaped to Yoshino, Takauji ASHIKAGA backed up Emperor Komyo from Jimyoin-to (the Northern court). As the Go-Daigo insisted that power remain on his side (the Southern Court), this was the beginning of the period of the Northern and Southern Courts.
Generally, it is said that Jimyoin-to's ancestors are the current Imperial Family; but the legitimate highbred of Jimyoin-to, Go-Kogon'in-ryu was extinguished after the generation of Emperor Shoko, son of Emperor Go-Komatsu, and strictly speaking the direct ancestor of the Imperial Family is the Fushimi-no-Miya Family, which was in the position of a cadet family (the descendant of Emperor Suko, Suko'in-ryu) of Jimyoin-to.