1) The Qin Dynasty (221-206 BC) was the first to unify China under Qin Shihuangdi, who standardized laws, currency, and script. Though short-lived, Qin built infrastructure like the Great Wall and Terra-Cotta Army.
2) The Han Dynasty (206 BC-220 AD) adopted Confucianism and developed bureaucracy, education, arts, and science like acupuncture. The Silk Road connected China to Rome under Han.
3) The Han collapsed due to northern invaders, dividing China into the Three Kingdoms of Wei, Shu Han, and Wu until reunification in 280 AD. This era saw the