The historian Li Yu accidentally traveled to the late Sui Dynasty and early Tang Dynasty and became Li Yuan's sworn brother. With modern knowledge, he innovated military technology, improved agricultural production, promoted scientific and technological progress, and helped the rise of the Li and Tang dynasties. He cleverly resolved the Xuanwu Gate Incident, changed Wu Zetian's destiny, and guided the Tang Dynasty to avoid historical traps. From the rise of troops in Taiyuan to the heyday of Zhenguan, from the prevention of the Anshi Rebellion to the elimination of the eunuch's dictatorship, Li Yu reshaped the Tang Dynasty with wisdom beyond the times. This is a legend in which time travelers change history, and it is also a wonderful collision between modern civilization and ancient wisdom.
Godly and nagging