Middle AgesGovernment & Law Wu Zetian becomes emperor 690 CENotable Wu Zetian declares her own Zhou dynasty and rules as China's only woman emperor. She expands the civil service examinations and patronizes Buddhism. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → First fired clay figures → First pottery → Copper smelting → Bronze Age begins → Shang dynasty → Zhou dynasty and the Mandate of Heaven → Spring and Autumn period → Legalism (Shang Yang) → Qin unifies China → Han dynasty → Sui reunifies China → Imperial examinations → Tang dynasty → Wu Zetian becomes emperor Community notesLoading notes… Learn more ranked by votesBookN. Harry RothschildWu Zhao: China's Only Woman Emperor ↗Editor's pickVideoSearch on YouTubeWu Zetian China's only female emperor ↗Editor's pick