Emperor Taizong of Tang

Emperor Taizong of Tang, personal name Li Shimin, was the second emperor of the Tang dynasty, ruling from 626 to 649. He is traditionally regarded as a co-founder of the dynasty for encouraging his father Li Yuan (Emperor Gaozu) to rebel against the Sui dynasty in 617, then played a pivotal role in defeating the dynasty's rivals and securing its rule over China. Taizong is considered one of the greatest emperors in Chinese history, and his reign became the exemplary model by which later emperors were measured. His era, the Reign of Zhenguan, is regarded as a golden age in ancient Chinese history and was required study for future crown princes. He continued to develop the imperial examination system for staffing the bureaucracy by merit.