They were a branch of the Kazanin family, FUJIWARA no Morozane line of the Northern House of the Fujiwara clan, and founded by Dainagon (major counselor) Sadatoshi NONOMIYA, a grandchild of Sadaijin (minister of the left) Sadahiro KAZANIN.
藤原北家藤原師実流花山院家の庶家で、左大臣花山院定熙の孫である大納言野宮定逸を祖とする。