The position of Jugo was created in 871 when the sessho (regent) of that time, FUJIWARA no Yoshifusa (who was a maternal relative of Emperor Seiwa), was granted nenkan, nenshaku and fuko by the emperor; subsequently, Jugo became firmly established as an institution of the Imperial Court when, during his tenure as sessho, FUJIWARA no Mototsune was granted zuishin hyojo (armed government officials who accompanied aristocrats as a mark of their dignity and to provide them with protection), ninjin, nenkan, and nenshaku by the emperor in the same way as the Sango would be.
准后は貞観_(日本)13年(871年)、清和天皇が外戚である摂政藤原良房に、三宮に準じて年官・年爵・封戸を賜ったのがはじまりであり、以後、良房の養嗣子　藤原基経が摂政在任中に、三后に准じて随身兵杖、任人、年官・年爵を賜ったことで准后が朝廷の正式な制度として定着した。