Late Sui Dynasty and Early Tang Dynasty: Natural Selection, Four Advances

Zhang Beihai died on the "Natural Selection", but woke up in a mass grave in the late Sui Dynasty. Thirteen-year-old Li Shimin put a knife on his neck. He said: "My name is Zhang Beihai. From today on, you will call me big brother." Thirty years later, the flag of the Tang Dynasty was planted all over the world. Li Shimin's heart ached: "Who are you?" Zhang Beihai looked at the stars and didn't answer. There are only four words engraved on his tombstone——