Emperor Seiwa
The is a line of the Japanese Minamoto clan that is descended from Emperor Seiwa, which is the most successful and powerful line of the clan. Many of the most famous Minamoto warriors, including Minamoto no Yoshiie, Minamoto no Yoritomo, the founder of the Kamakura shogunate; and Ashikaga Takauji, the founder of the Ashikaga shogunate, belonged to this line. Tokugawa Ieyasu (1543–1616), founder of the Tokugawa shogunate, also claimed descent from this lineage. The family is named after Emperor Seiwa, who was the grandfather of Minamoto no Tsunemoto who founded the Seiwa Genji. Emperor Seiwa was father of Imperial Prince Sadazumi (貞純親王 "Sadazumi Shinnō") (873–916), who was in turn the father of Minamoto no Tsunemoto (源経基) (894–961), founder of the Seiwa Genji, from whom the Seiwa Genji descended. Many samurai families belong to this line and used "Minamoto" clan name in official records, including the Ashikaga clan, Hatakeyama clan, Hosokawa clan, Imagawa clan, Mori, Nanbu clan, Nitta clan, Ogasawara clan, Ōta clan, Satake clan, Satomi clan, Shiba clan, Takeda clan, Toki clan, Tsuchiya clan, among others. The Shimazu clan and Tokugawa clan also claimed to belong to this line.