The origin of the Tsutsui clan is not perfectly clear, but it is known that they were a local clan in Yamato Province and were the shuto (monk-soldiers) of Kofuku-ji Temple in the middle ages.
筒井氏の起源については必ずしも明らかではないが、大和国の土豪であり、中世には興福寺の衆徒（しゅと）であった。