Tōtōmi Province
Aoyama Tadao was the second son of Aoyama Munetoshi, the daimyō of Hamamatsu Domain (Tōtōmi Province), and was born in Komoro, Shinano Province. On his father's death in 1679, he became 4th head of the Aoyama clan and daimyō of Hamamatsu Domain.