In the online book review area, a friend proposed that Cheng Yanjin's title is "Lu Guogong".Here's an explanation.The title of the founding hero of the early Tang Dynasty was conferred in both the Wude and Zhenguan periods.Many "national dukes", the titles awarded during the Wude period and the Zhenguan period are not the same.For example: Cheng Biting Jin, during the Wude period, Li Yuan named him "Duke of Suguo", and in the eleventh year of Zhenguan, Li Shimin renamed him "Duke of Lu"; Qin Qiong, during the Wude period, Li Yuan named him "Yiguo Gong", and in the thirteenth year of Zhenguan, Li Shimin renamed him "Hu Guogong"; Li Jing, during the Wude period, he was named the Duke of Yongkang County, Zhenguan was awarded the title of "Acting as the Duke of the Country" in the fourth year, and Zhenguan was renamed the "Duke of Weiguo" in the eleventh year of Zhenguan; Li Taoji, Wude was awarded the title of "Lai Guogong", Zhenguan was awarded the title of "Cao Guogong" in the fourth year, and Zhenguan was renamed "British Gong" in the eleventh year; The eldest grandson Wuji, in the Wude period, was awarded the title of "Shangdang County Gong", in the first year of Zhenguan, he was named "Duke of Qi", and in the eleventh year of Zhenguan, he was renamed "Duke of Zhao"; Fang Xuanling, Zhenguan was awarded "Xing Guogong" in the first year, Zhenguan was awarded "Wei Guogong" in the fourth year, and Zhenguan was renamed "Liang Guogong" in the eleventh year; Du Ruhui, initially named "Cai Guogong", and later changed to "Lai Guogong"; Gao Shilian, first named "Xu Guogong", and later changed to "Shen Guogong"; Wei Chigong, first named "Wu Guogong", and later changed to "E Guogong"; Hou Junji, first named "Lu Guogong", later changed to "Chen Guogong"; When I was writing this book, whenever I encountered people and events that really existed in history, I would repeatedly check the information against the old Tang Dynasty books, the new Tang Dynasty books, and Zizhitong, and strive to minimize the mistakes.Even if this is the case, mistakes are inevitable.If you have any questions in the process of reading the book, you may wish to ask them in the book review area, and I will definitely answer them.If it's really a mistake in my book, I'll try to correct it.Finally, thank you all for your enthusiastic help and support: