Question: When did Li Ying (Prince)'s father die?
Sentence (from "Li Ying (prince)"): Li Ying (李瑛) (died 737), né Li Siqian (李嗣謙), known from 725 to 736 as Li Hong (李鴻), was a crown prince of the Chinese dynasty Tang Dynasty during the reign of his father Emperor Xuanzong.
Relevant evidence: Yes