Katahara family

...They were powerful warriors in Mikawa Province in the late Middle Ages. Their head family changed their surname to Tokugawa in 1566 (Eiroku 9) and became the Shogun family of the Edo period, and their family members became daimyo and hatamoto (samurai retainers) (Figure).
[Origin of the Matsudaira clan]
According to the Edo Shogunate-certified origin story of the Matsudaira clan, a descendant of the Tokugawa clan, a branch of the Nitta clan of the Seiwa Genji clan, left their home town of Tokugawa-go, Nitta-gun, Kamino Province, due to persecution by the Ashikaga clan, became a Jishu monk, and wandered around the country. During the reign of Chikauji, he became the husband of the daughter of the Matsudaira clan, a local lord in Matsudaira-go, Kamo-gun, Mikawa Province, and this is how the Minamoto Matsudaira clan began, and the surname was "reverted" during the reign of Ieyasu, the ninth generation descendant.

*Some of the terminology that refers to the Katahara family is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…中世後期の三河国の有力武士で，惣領家は1566年(永禄9)徳川と改姓して江戸時代の将軍家となり，一族は大名，旗本となった（図）。
［松平氏の発祥］
　江戸幕府公認の松平氏発祥譚では，清和源氏新田氏の庶家徳川氏の末裔は，足利氏の迫害のため，本貫の地上野国新田郡徳川郷を退去して時宗の僧となって諸国を流浪し，親氏（ちかうじ）の代に三河国加茂郡松平郷の土豪松平氏の娘婿となったのが，源姓松平氏のはじまりで，9代の後裔家康の代に〈復姓〉したという。…

※「形原家」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報