Tang Taizong
Liu Yizhi was born in 631, during the reign of Emperor Taizong of Tang. His grandfather Liu Xingzong (劉興宗) had served as an army officer during Chen Dynasty, and his father Liu Ziyi (劉子翼) was an official and scholar of renown during Sui Dynasty and the early Tang Dynasty, dying early in the reign of Emperor Taizong's son Emperor Gaozong.