The originator of the Hosokawa clan is said to be MINAMOTO no Yoshikiyo (Yada no Hangandai) who was the first illegitimate child (who were born out of wedlock) of Yoshiyasu ASHIKAGA, the founder of the Ashikaga clan.
細川氏の開祖は、足利氏の祖・足利義康の庶長子である源義清(矢田判官代)とされる。