When the Kamakura bakufu (Japanese feudal government headed by a shogun) was established towards the end of the 12th century, nine provinces in the Kanto region became chigyo-koku provinces of Kamakura-dono (lord of Kamakura), or provincial territories belonged to the Kamakura bakufu.
12世紀終わりに鎌倉幕府政権が樹立すると、関東の9か国が鎌倉殿の知行国関東御分国となった。