酒井氏
The "fudai" Sakai clan originated in 14th century Mikawa Province. The Sakai claim descent from Minamoto Arichika. Arichika had two sons: one of them, Yasuchika, took the name Matsudaira; and the other son, Chikauji, took the name Sakai — and this samurai ancestor is the progenitor of this clan's name.