The Nagao family was a vassal of the Uesugi family, furthermore, the real family name of the Uesugi family was Fujiwara while that of Nagao family was Kammu-Heishi (Taira clan).
長尾家は上杉家の家臣筋であり、しかも上杉家の本姓が藤原氏なのに対して長尾家は桓武平氏であった。