Sadahisa greatly contributed to the establishment of the Ashikaga Shogunate by actions known for his assistance of Takauji who escaped to Kyushu as he incurred a temporary loss in a battle and so on, and by beating back Kikuchi's force in the Battle of Tatarahama which paved the way for Takauji's comeback.
貞久は、一時敗れて九州へ逃げのびた尊氏を助け、多々良浜の戦いで、菊池氏勢を撃退、尊氏の巻き返しに協力するなど、足利幕府成立に大きく貢献した。