Tadaoki's actual father Yusai HOSOKAWA was a vassal, his adoptive father was a relative of Terutsune HOSOKAWA (Hosokawa-Oshu family), and he married Mitsuhide AKECHI's daughter Tamako (also known as "Gracia HOSOKAWA").
実父は幕臣・細川幽斎、養父は一族の細川輝経（細川奥州家）、正室は明智光秀の娘・玉子（通称は細川ガラシャ）。