Guo Ziyi
Li You was born in 795, during the reign of his great-grandfather Emperor Dezong. At that time, his father Li Chun was the Prince of Guangling, and his grandfather Li Song was Emperor Dezong's crown prince. Li You's mother Princess Guo was Li Chun's wife and a granddaughter of the prominent general Guo Ziyi—her parents were Guo Ziyi's son Guo Ai () and Princess Shenping, a sister to Emperor Dezong. Li You was Li Chun's third son. At some point, Li You was created the Prince of Jian'an.