In the Kamakura and Muromachi periods, major senior vassals and shugo daimyo (provincial military governors, who became feudal lords) took important roles and were sometimes even stronger than the shogunal family or regent.
鎌倉・室町幕府においては、（時によっては将軍家・執権すらしのぐほどの）有力御家人・守護大名が要職に就いていた。