The origin of fudai daimyo comes from the fact that Ieyasu TOKUGAWA, when transferred to Kanto region under the TOYOTOMI regime, granted land to build a castle and a position of daimyo to his major military commanders in the hereditary vassalage, thus making them serve as hanpei (the guarding wall of the sovereign) to support the TOKUGAWA clan.
譜代大名のはじまりは徳川家康が豊臣政権のもとで関東地方に移封された際に、主要な譜代の武将に城地を与えて大名格を与えて徳川氏を支える藩屏としたことに由来する。