When Yang Di was in Yangzhou, he tried his best to protect the people. When he was emperor, digging the Grand Canal was a pioneering work in the history of China. In addition, Yang Guang's literary talent is extremely high. You can search his poems, which are very atmospheric. According to historical records, Yang Guang is "good at writing". Tang gaozu posthumous title Yang Guang. After the regime change, it is not credible that later generations gave their hobbies to the former. Because Li Shimin's father was a veteran of the Sui Dynasty, it was a bit indefensible to seize the throne of others, so Li Shimin, who later mastered the right to speak, completely subverted the image of Emperor Yang Di when writing the history of the Sui Dynasty.