In the cabinet officials of the Shogunate in the early Edo period, Tokugawa family members, who were deeply trusted by Ieyasu TOKUGAWA, such as Sadakatsu MATSUDAIRA and Tadaakira MATSUDAIRA, (Masayuki HOSHINA in the Ietsuna TOKUGAWA era occupied a similar position), or senior vassals, such as Naotaka II and Tadayo SAKAI (there are different opinions about whether both of Ii and Sakai were appointed to the Tairo post) played a role of Genro (an elder statesman), and it is considered that this Tairo post was established for having this role assumed by the senior member of Roju.
初期の幕閣では松平定勝や松平忠明といった徳川家康の信頼が厚い親族（徳川家綱時代の保科正之もこれに近い）や井伊直孝・酒井忠世などの重臣（井伊・酒井両名が大老に就任したかどうかについては意見が分かれている）が元老としての役割を果たしていたが、その役割をベテランの老中に担わせた職掌とみることができる。