The clan was a powerful force in the Kantō region during the Heian period (794–1185).
The clan was based in the city of Ashikaga, in Shimotsuke province, over which Fujiwara no Hidesato was Imperial Governor (kami).
In 1161, the position of jitō (manor lord) of Ashikaga city in Shimotsuke province came to be disputed between the Koyama clan, descendants of Fujiwara no Hidesato, and Utsunomiya Ietsuna, a member of the Shiroi Utsunomiya clan, also descended from the Fujiwara, whose son Toshitsuna controlled several thousand hectares of land in that area.
The dispute eventually ended in Hidesato's descendants being granted the post of shugo (shogunal governor) in the northern Kantō.
Following the Genpei War, Yoritomo established the Kamakura shogunate, and the descendants of Ashikaga no Nariyuki, now known as the Sano, Ōgo, and Asonuma families, came to serve as direct vassals (gokenin) to the shōgun.