When MINAMOTO no Yoritomo became Kamakura-dono (lord of Kamakura) as a result of the Jisho-Juei War and established the Kamakura bakufu (Japanese feudal government headed by a shogun), shogunal retainers (of the Kamakura bakufu) who were samurai serving kamakura-dono were substituted for the old gunji, goji, shokan and appointed to jito (manager and lord of manor).
治承・寿永の乱によって源頼朝が鎌倉殿となり鎌倉幕府を開くと、鎌倉殿に臣従した武士である御家人をこれまでの郡司、郷司、荘官に代えて地頭に任命した。