Emperor Seiwa
The clan was descended from the Seiwa Genji, a branch of the Minamoto clan, and ultimately from Emperor Seiwa himself, through the Ashikaga clan. It produced many prominent officials in the Ashikaga shogunate's administration. In the Edo period, the Hosokawa clan was one of the largest landholding "daimyō" families in Japan. In the present day, the current clan head Morihiro Hosokawa, has served as Prime Minister of Japan.