According to the old people, there used to be a drum tower in the middle of Shifang Road and Drum Tower Street in Ningjin County, and whenever night fell, the drums reported by the drum tower spread out to the surrounding areas, and the eight townships in ten miles could be heard, and at that time, a scene that belonged to Ningjin was called "Twilight Drum of Ningjin". The origin of this bell and drum tower is related to a cabinet chief assistant during the orthodox years of the Ming Dynasty, who is the Cao Nai we will introduce today. Cao Nai (1404-1449 AD), also known as Wan Zhong, nicknamed Mr. Hengshan. In the eighth year of Ming Xuande (1433), he was given the title of Emperor Zhongzhong of the Imperial Examination, and was officially awarded the title of Hanlin Academy, promoted to a bachelor of the Hanlin Academy, a left attendant of the Ministry of Rites, and later to the first assistant of the cabinet, and in the fourteenth year of the Ming Dynasty (1449), he accompanied Emperor Ming Yingzong Zhu Qizhen to personally march to Datong and died in Tumu Fort. At present, there is also the tomb of Zhuangyuan (Yiguan Tomb) in the Eastern King of Ningjin, the original Zhuangyuanfang is located in the back street of Wenmiao Temple on Shifang South Road, and the University Shifang is located in the north of Zhuangyuanfang, all of which were destroyed. In 2016, Zhuangyuanfang was re-established on Shifang Road. Records of Emperor Ming Yingzong. Volume 181. VI reads: "Nai Mingmin is a kind of person, a good judgment in the face of things, a discussion, and a stepmother who is aggrieved and obedient, and who is pleased with him." After the feast, ming tangles were clear and smooth, enlightening Chenxiao, although the left and right attendants were also happy to hear. Wang Zhen is a dictatorship, fiercely self-conscious, no one dares to be disobedient, only Nai nai follows the matter, and what he says is more common and obedient. And stationed in Xuanxuan Mansion, Nai urged not to enter lightly, and Zhen did not listen. "In Beijing, the inscription of the Guozi Jianjin soldier is: He has both talent and knowledge, is sensitive and decisive, and his righteousness is awe-inspiring, and he is deeply valued by the Yingzong. He died in 1449 during the "Civil Revolution". Cao Nai was a clean and honest official, a righteous person, and a scholar with a good reputation.
