Emperor Taizong of Tang (January 23, 599 CE – July 10, 649 CE), personal name Lǐ Shìmín, was the second emperor of the Tang Dynasty of China, ruling from 626 to 649 CE. As he encouraged his father, Li Yuan (later Emperor Gaozu) to rise against Sui Dynasty rule at Taiyuan in 617 CE and subsequently defeated several of his most important rivals, he was ceremonially regarded as a co-founder of the dynasty along with Emperor Gaozu.