Hosokawa Tadaoki was a Japanese samurai warrior of the late Sengoku period and early Edo period. He was the son of Hosokawa Fujitaka with Numata Jakō, and he was the husband of a famous Christian convert (Kirishitan), Hosokawa Gracia. For most of his life, he went under the name of Nagaoka Tadaoki that had been adopted by his father and was related to a town that was in their domain. Shortly after the victory at Sekigahara, Nagaoka Tadaoki reverted to his original name Hosokawa Tadaoki.

Hosokawa Fujitaka , also known as Hosokawa Yūsai , was a Japanese samurai daimyō of the Sengoku period. Fujitaka was a prominent retainer of Ashikaga Yoshiaki, the last Ashikaga shōgun. When he joined the Oda, Oda Nobunaga rewarded him with the fief of Tango and went on to become one of the Oda clan's senior generals.