Who is the only queen in the history of China?

Only Wu Zetian officially acceded to the throne. Lv Hou, the wife of Liu Bang in the Western Han Dynasty, had no real power. Xiao Taihou was the wife of Empress Dowager Cixi in the early Eastern Jin Dynasty. Shi Yang (579-670), the mother of Wu Zetian, was born in Guanlong, the daughter of Yang Da, the prime minister of Sui Dynasty. She married into the Wu family at the age of nearly 40 (some people say 44) after the death of Li, with Li Yuan as the background and Princess Guiyang (Yang's cousin) as the matchmaker. She has three daughters, the eldest daughter married Helan Yueshi, and the third daughter married Guo, who died young. The second daughter is Wu Zetian.