Background
Tadatoshi was the son of Aoyama Tadanari, a Tokugawa vassal of the Sengoku period who was born in Mikawa Province. Tadatoshi, like his father, was a Tokugawa vassal, and was famous for his role as the third shogun Iemitsu's teacher.
Tadatoshi was the son of Aoyama Tadanari, a Tokugawa vassal of the Sengoku period who was born in Mikawa Province. Tadatoshi, like his father, was a Tokugawa vassal, and was famous for his role as the third shogun Iemitsu's teacher.
He became a daimyō in 1603, when Tokugawa Ieyasu granted him the domain of Edosaki. Under command of Hidetada Tokugawa served with distinction in the Osaka-in in 1614 (Toyotomi Clan, the opposing power to the Tokugawas, was overthrown). With Toshikatsu Doi, Tadayo Sakai and others was appointed private teacher and assistant to young Iemitsu, third Shogun of Tokugawa Dynasty.Was an assistant of master with rectitude guiding him in keeping his words and deads clean and upright. Later was found guilty of some crime and was deprived of his feud; afterwards was acquitted.