李承乾
In 645, when Emperor Taizong attacked Goguryeo and left his crown prince Li Zhi (who replaced Li Chengqian in 643 after Li Chengqian was discovered to have plotted to overthrow Emperor Taizong) in charge of logistics at Ding Prefecture (定州, roughly modern Baoding, Hebei), Gao was left there as well to assist Li Zh, along with Liu Ji, Ma Zhou, Zhang Xingcheng, and Gao Jifu. When Li Zhi heard and decided important matters, he set up a seat for Gao next to him, but Gao declined the honor.